Studies of the effect of immigration on homicide in U.S. cities have reported mostly null or negative results. These studies suffer from a failure to weight by population size and the lack of a credible identification strategy. Using data from the Census and the Uniform Crime Reports, 146 U.S. cities in the year 2000 are analyzed using weighted instrumental variables (IV) regressions to overcome these limitations. Estimates are insignificant, and none suggest a substantial negative effect of immigration on homicide, a finding that is replicated with 1990 data. Model comparisons indicate that conventional specifications exaggerate the beneficial effect of immigration somewhat.