A typology of mixed farming systems in the semi-arid zone of sub-Saharan Africa is needed: (1) to order diversity, (2) to assist development interventions and technical recommendations, and (3) to provide a framework for monitoring change, both economic and environmental. A review of the available typological principles suggests that a scheme based on intensification and crop-livestock integration has both theoretical and practical value. The scheme is applied to a sample of (43) farming systems, for which published characterizations are available. Measures of association between population densities, livestock densities, intensity ratings and crop-livestock integration ratings support the hypothesis that these variables are functionally and consistently related, though not all associations are statistically significant. The scheme proposed cannot be used to predict environmental degradation, which is determined in part by interactions with exogenous variables. But it does provide a robust framework for understanding the time-trajectories of farming systems along degradational or conservationary pathways. (CAB Abstract)