Using international data for 100 countries, we test two hypotheses derived from Bonger's Marxian theory of crime. The analyses support the hypothesis that the degree of capitalism significantly predicts homicide rates, but they fail to confirm that the de‐moralization of the population (loss of moral feelings for others) mediates the relationship between capitalism and homicide. Although capitalism is not the best predictor among those considered, overall, the results underline the importance of Bonger's ideas because both capitalism and corruption (our indicator of de‐moralization) show reasonably strong relationships with homicide rates and compete with other variables commonly used as predictors of international homicide rates. The results confirm the usefulness of attempting to subject Marxian ideas to positivist, quantitative tests, with an eye to integrating Marxian theories with other mainstream theories, such as institutional anomie theory.