In this article I address the question: does ethnic inequality — systematic economic disparities among ethnic groups — have an impact, net of other factors, on a community's rate of homicide? The results of previous studies contradict one another. This contradiction suggests a need to reexamine thelogicof the ethnic/racial inequality hypothesis and the measurement of its key variables. I argue that there are social processesmediating ethnic inequalityand homicide, and that these must guide the measurement of the former if we wish to obtain reasonably conclusive results. After presenting an account of the pertinent theory, I introduce a measure of ethnic inequality not previously found in the criminal etiology literature. The results confirm the usefulness of this measure. Empirical findings based on 1980 data for a sample of 150 SMSAs show that ethnic inequality is a strong predictor of the rate of homicide, and that it remains the single strongest predictor even after variables operationalizing poverty, general economic inequality, regional culture, race, and anomie are taken into account.