This article from the Telegraph about street crime in Barcelona is sadly all too true. Muggings, pickpocketings, and purse-snatchings are much too common. Tourists who appear to be well-off are the main--really only--targets. Locals are rarely molested. The main culprits are Arab street kids. This is not racism. It is a fact. Holes in the Spanish legal and judicial system prevent us from either locking up the little bastards or deporting them. Yes, they were born poor--they now have plenty of ill-gotten cash and flashy name-brand sports clothes--and have had crappy lives. No, that doesn't give them the right to victimize those people who were not born poor and have not had crappy lives.

The Barcelona Tourist Board's response, which is provided by the Telegraph, is a lie. Nothing is being done, at least not effectively, against the street-crime wave that has been going on for several years.

For visitors to Barcelona:

1) You are a target. They recognize you as a foreigner. Remember this at all times.
2) They will not kill you. They very well might hurt you, normally in a take-down from behind.
3) Do not walk the streets wearing expensive clothes or jewelry. My mother stubbornly refuses to listen to me; she won't take off her (modest) jewelry in Barcelona. Something bad is going to happen one day. 4) Do not carry around camera equipment casually. If you want to take photos, plan to spend a day dedicated exclusively to that. Then stick the damn camera in your hotel safe. Or get one of those disposable cameras that cost ten bucks.
5) The Raval, the area to the left of the Ramblas, going up, is a no-go area after dark unless you are 22 with a group of four friends. If you are vulnerable--a woman, a small man, an older person--stay out of there after dark and be damned careful during the day.
6) The Ramblas is dangerous. Go there but be careful. You won't be mugged during the day--that's when the pickpockets operate. You very well might be violently mugged after dark in the Ramblas itself. It happened to me. Watch out for crowds of tourists at street spectacles.
7) The Plaza Real is dangerous. Party there at your own risk. The scene there isn't attractive for anyone not looking to get wasted anyway.
8) The rest of the Old City, to the right of the Ramblas going up, is a better and a safer area than the Raval, but still watch yourself and don't go down dark black alleys. It's better if there are at least two of you. EXCEPTION: the area right around the Picasso Museum. Watch it around there.
9) Consider spending more money and staying--and eating--in the wealthier and safer Eixample (the area in the center of the city with large, octagonal blocks, "north" of the Old City) or Sarria-Sant Gervasi (the area near and above the upper Diagonal). There are fewer tourists and virtually no muggers in those parts. Watch out for pickpockets in the area around the Pedrera and around the Park Guell.
10) WATCH OUT FOR SMALL GROUPS OF ARAB TEENAGERS. I'm sorry. I don't care if that offends anyone. Stay away from them. They will rob you and they don't mind if they have to hurt you.
11) The Barcelona city government is negligent in not clarifying the risks that a visit to Barcelona incurs. Barcelona is safe enough if you behave yourself as if you were in a dodgy part of Chicago or New York. If you do not take precautions, YOU WILL BE A VICTIM. One of these days those damned kids are going to kill a tourist from one of those luxury cruise ships and then the shit is going to hit the fan.
12) The Barcelonese themselves don't really give a shit. You'll get sympathy, but you'll also get "well, everyone knows that's a bad part of town" and "well, you shouldn't have had your wallet in your back pocket" and "we're sorry but there's nothing we can do." They don't particularly care because they themselves are rarely victims and you are just another tourist.

Anecdote. A couple of years ago I was in KC and I went to get my drivers license renewed six months before it ran out. The clerk down at the DMV got a little suspicious and asked why. I replied that I was going abroad and just wanted to make sure I had a valid license. She asked where and I said Spain. She said, "Oh, you'd better watch out in Barcelona, it seems like half the people who come in here for new licenses got robbed in Barcelona." If the first thing that comes to the mind of a typical, standard American, a clerk at the Kansas Department of Motor Vehicles, when she thinks of Spain, is "Barcelona is dangerous" and not "Spain is beautiful", then we've got a problem, Houston. Over and out.

Here is the US State Department's take on crime in Spain from a tourist's perspective. Read it.

CRIME: While most of Spain has a moderate rate of crime and most of the estimated one million American tourists have trouble free visits to Spain each year, street crimes against tourists occur in the principal tourist areas. Madrid and Barcelona, in particular, report incidents of muggings and violent attacks, and older tourists and Asian Americans seem to be particularly at risk. Criminals frequent tourist areas and major attractions such as museums, monuments, restaurants, outdoor cafes, Internet cafes, hotel lobbies, beach resorts, city buses, subways, trains, train stations, airports, and ATM machines.

In Barcelona, a number of attacks have been reported on Las Ramblas, near the Picasso Museum, in the Gothic Quarter, in Parc Güell, in Plaza Real and on Montjuic. In Madrid, incidents have been reported in most major tourist areas, in the area near the Prado Museum, near Atocha train station, in Retiro Park, in areas of old Madrid including Sol and El Rastro flea market, near the Royal Palace and in Plaza Mayor. Travelers should remain alert to their personal security and exercise caution. Travelers are encouraged to carry limited cash, one credit card, and a copy of their passport; leaving extra cash, credit cards, passports and personal documents in a safe location. When carrying documents, credit cards or cash, you are encouraged to secure them in a hard-to-reach place and not to carry all valuables together in a purse or backpack. Crimes occur at all times of day and night and to people of all ages.

Thieves often work in teams or pairs. In most cases, one person distracts a victim while the accomplice performs the robbery. For example, someone might wave a map in your face and ask for directions or "inadvertently" spill something on you. While your attention is diverted, an accomplice makes off with the valuables. Attacks have also been initiated from behind, with the victim being grabbed around the neck and choked by one assailant while others rifle through or grab the belongings. A group of assailants may surround the victim, often in a crowded popular tourist area or on public transportation, and only after the group has departed does the person discover he/she has been robbed. Purse-snatchers may grab purses or wallets and run away, or immediately pass the stolen item to an accomplice. A passenger on a passing motorcycle sometimes robs pedestrians. There have been several reports of thieves posing as plainclothes police officers sometimes beckoning to pedestrians from cars. American citizens are encouraged to deal with uniformed law enforcement personnel only. Some attacks have been so violent that victims have needed medical attention.

Theft from vehicles is also common. Items high in value like luggage, cameras, laptop computers, or briefcases are often stolen from cars. Travelers are advised not to leave valuables in parked cars, and to keep doors locked, windows rolled up and valuables out of sight when driving. "Good Samaritan" scams are unfortunately common, where a passing car or helpful stranger will attempt to divert the driver's attention by indicating there is a flat tire or mechanical problem. When the driver stops to check the vehicle, the "Good Samaritan" will appear to help the driver and passengers while the accomplice steals from the unlocked car. Drivers should be cautious about accepting help from anyone other than a uniformed Spanish police officer or Civil Guard.

While the incidence of rape and sexual assault is statistically very low, attacks do occur. Americans should not lower their personal security awareness because they are on holiday. Spanish authorities have warned of availability of so-called "date-rape" drugs and other drugs, including "GBH" and liquid ecstasy.

American citizens have been victims of lottery or advance fee scams in which a person is lured to Spain to finalize a financial transaction. Often the victims are initially contacted via internet or fax and informed they have won the Spanish Lottery (El Gordo), inherited money from a distant relative, or are needed to assist in a major financial transaction from one country to another. For more information, please see the information sheet on the Bureau of Consular Affairs website at http://travel.state.gov/scams.html.

Here's Barcelona Business on safety in Barcelona:

Catalonia is Spain's third most frequently visited province, with Britons the most numerous tourists, followed by Germans. Barcelona was Britons' most popular 'city break' destination last year. Rising street crime reported in the UK press has caused more concern than the statistically miniscule risk of being hurt by ETA bombs.

Tourists in Barcelona are targeted by gangs using strangleholds and carrying knives and bottles. Baggage is snatched from hotel lobbies and tour coach unloading spots. Police inaction and a judicial vacuum encouraging reoffenders tempt hundreds of foreign professional criminals to the city during the tourist season. Official figures show that a crime is committed in the city every two minutes, up 7% on last year, with 65% of reports for assault or theft. Many attacks go unreported.

Criminal activity tends to break down ethnically: while eastern Europeans use various scams on La Rambla, the Old Town back streets are best for bag snatching, often at the hands of young north Africans. The situation is a disaster for racial harmony in a city only just coming to terms with immigration.

Armed international gangs hit Barcelona jewellers, well-stocked for the season, and bands of highwaymen (usually termed 'Peruvians' by the Spanish press) cruise Catalonia's highways on the lookout for foreign numberplates. Foreign motorists are more at risk this summer due to the confusing renaming of Catalonia's highways, with route names not appearing on international tourist maps (see Story, Roads renamed).