The Chicago Tribune reports (http://trib.in/HwHxiE ) that police statistics show nonfatal shootings also rose sharply in the first quarter.
Chicago police and Mayor Rahm Emanuel say the city has increased efforts to combat gang crime, including adding officers and other resources to trouble spots.
Statistics show 120 homicides from Jan. 1 through April 1 compared to 75 in the same period in 2011.
Criminologists say unseasonably warm weather might have contributed because more people are outside.
Experts say it's too early to draw hard conclusions from the early data, warning it could be misleading.
Chicago has been at historic lows for homicides in recent years.
