We investigate the determinants of agricultural productivity in a panel of 27 tropical developing countries from 1984 to 2005 and test whether the coefficients of the right-hand side variables are significantly different in sub-Sahara Africa. We find evidence that the point estimates of fertilizer usage, telephones, tractor usage, rainfall and irrigation are positively and significantly related to agricultural productivity in the tropics. We also show that sub-Saharan Africa is different in several respects. For instance, we find no evidence that fertilizer is associated with greater agricultural productivity in the African sample. Also, while the coefficient on infrastructure is positively associated with agricultural productivity in the full sample, its quantitative effect is smaller in sub-Saharan Africa. As a robustness test, we experiment with an alternative measure of tropicality and find that the results are broadly similar.