The opportunity and motivation effects underlying criminal activity presented in Cantor and Land (1985) are revisited. It is argued that a full appreciation of these effects requires examination of the evolution of criminal activity over the business cycle rather than in relation to simple measures of unemployment, as has been considered often in the literature. Using the derived cyclical components of a number of socio-economic indicators, the empirical evidence in support of the proposed theoretical relationships is examined. It is found that in contrast to the results obtained when using unemployment, consideration of alternative cyclical indicators provides very strong support for the presence of opportunity and motivation effects of the form predicted by Cantor and Land (1985). An interesting distinction between results for property and violent crimes is noted and discussed.