This paper examines sources of agricultural growth in sub-Saharan Africa. Growth in the stock of traditional inputs (land, labor, livestock) remains the dominant source of output growth. Growth in modern input use was of secondary importance, but still accounted for a 0.2-0.4% annual growth rate in three of four sub-regions. Econometric results support earlier studies that suggest that land abundance may be a constraint on land productivity growth. Growth in agricultural exports and historic calorie availability had positive impacts on productivity. These latter results suggest that positive feedback effects exist between export performance and food security on one hand and agricultural productivity on the other.