Pennsylvania has ranked either first or second in the study for the past five years, said Josh Sugarmann, executive director of the Violence Policy Center.
"Pennsylvania residents should be deeply concerned and very troubled," he said. "What this shows is that there's a consistent problem."
Chad Dion Lassiter, race professor at the University of Pennsylvania and West Chester University, said the stats were "extremely alarming."
"You let three white men die in one given Saturday because of gun violence, there would be an uproar," he said. "But here in Philadelphia, if three black men don't die in one weekend, we wonder what was going on. Was there a sporting event or something happening?
"The larger society does not put value on the price of a black body."
In the study, Pennsylvania came in second only to Missouri, which had a black homicide rate of 39.9 per 100,000.
New Jersey was 17th with 239 victims, or 18.11 per 100,000, and Delaware was 13th with 36, or 18.73 per 100,000.
Other data found that 89 percent of all of Pennsylvania's victims were killed with guns and that only 47 of the 449 black homicide victims were women.
According to the study, the national homicide rate for all races in 2008 was 4.93 per 100,000, and the national homicide rate for whites was 2.99 per 100,000.
Lassiter attributed the high rate of black homicides in Pennsylvania to the decline of both the family system and moral values. He said families need to be engaged, mentors need to be created, young men need to be taught communication, and stricter gun laws need to be enacted to start addressing the problem.
"We have to be able to cross over on the other side to our white allies and say, 'It's all of our problem,' " he said. "This is where race converges. They are all of our children."
As of yesterday, Philadelphia already had 25 homicides for the year, which is the highest since 2007, when the city marked 28 by Jan. 26.
The city had 331 homicides in 2008, the year of the study, which was down from 391 in 2007. There were 306 homicides last year.