I'm assuming you are only curious about major cities. Right now, it is thought that the homicide rate of Caracas Venezuela is currently at least 110 (per 100,000 population a year). And this does not even count questionable police executions, meaning that it is probably actually much more violent to live there than even the semi-official 110/100,000 tally would lead you to believe.
It should be noted though, that the more homicide crazy a country is, the more likely it does a poor job of recording and reporting data of this kind. It wouldn't surprise me (if one could look into a crystal ball to see the absolute truth) if the actual homicide capital of the world weren't a mid sized South African, Honduran, or former Soviet Bloc city.
I would like to point out as well that many would consider the military, genocidal, and terrorism deaths a city sustains should also count as "murder rate" or at least be added into the mix if we tweak the question to "What is the most dangerous city in the world?". As I write this at the end of 2009, it's not as relevant of a question as in years past, because there isn't an intense war taking place right now. But go back to 1994-95 in Grozny during the first Chechen War, and you had a populace that is estimated to have lost 1/10 citizens during just a 5 week period. Making it almost 100 times more dangerous than Caracas probably is today.
See my website www.violentdeathproject.com for more random violent death tidbits and information.
The city with the highest murder rate in 2011 was Caracas, Venezuela.
In recent years, the city of Jacksonville in Florida has had the highest murder rate compared to other cities in the state.
Russia has the highest murder rate in Europe. However, this includes all of Russia. Estonia is the wholly European country with the highest murder rate.
Flint, Michigan had the highest murder rate in the US for 2010.
Albany, Georgia, believe it or not. I'm still looking for that rate.
Anaheim.
Philly
As of September 1, 2011, Miami
Stockton, CA had their highest murder rate in 2012.
Which state had the highest murder rate in 2011?Read more: Which_state_had_the_highest_murder_rate_in_2011
which city/state has the highest murder rate so far this year
Gary Indiana had a murder rate of 58 per 100,000 highest of any city with a population of at least 100,000 = Murder Capital