In this paper, we examine and compare the impact of social disorganization, including recent immigration, and other predictors on community counts of black and Latino motive-specific homicides in Miami and San Diego. Homicides for 1985 to 1995 are disaggregated into escalation, intimate, robbery and drug-related motives. Negative binomial regression models with corrections for spatial autocorrelation demonstrate that there are similarities and differences in effects of social disorganization and other predictors by motive-specific outcomes, as well as for outcomes across ethnic groups within cities and within ethnic groups across cities. Recent immigration is negatively or not associated with most outcomes. Overall, the study shows the importance of disaggregating homicide data by race/ethnicity and motive and demonstrates that predictions based on existing theories are qualified on local conditions.