Since the 1970's, studies have consistently found that countries with higher levels of income inequality tend to have higher levels of homicide; however, there has yet to be proposed a convincing theory about the causal processes that generate this stable, positive association between economic inequality and homicide. One of the proposed theories examined in this article is the societal development thesis proposed by Messner (1982), based in Durkheim's societal development thesis presented in "The Division of Labor in Society." Messner theorizes that as societies expand, inequalities result in the course of labor divisions that distribute wealth unequally. This inequality results in perceptions of injustice, social anomie, and consequently the passions and frustrations that lead to homicide. A second theory critiqued is the deprivation thesis proposed by Jacobs (1981), which posits that economic inequality is directly related to the level of crime across macro-social units because it produces feelings of frustration and jealousy among the least affluent members of a community. Homicide increases result from such a condition. The authors of this article propose a new integrated theory that draws on aspects of the two theories critiqued. It argues that homicide rates increase when economic inequality leads to a decline in the moral authority of conventional society, thus reducing society's capacity to develop informal social controls and achieve compliance with formal social controls. This moral decline does not occur if economic inequalities result from differences in income due to differing pay for occupations that require different talents ("achieved" economic inequality), but rather when economic inequality is a structured imposition unrelated to occupational skills and knowledge ("ascribed" economic inequality). 4 notes and 73 references