This study investigates how farmers allocate their available farm land under various drivers of crop choice. Also investigate the determinants and trends of crop area and income diversification. Use panel data from nationally representative household-level surveys for Nigeria and Uganda that contain rich socioeconomic and demographic information, merging the survey data with detailed weather shocks and land cover change. Use both the shares of land and income of the major crop categories to measure farmers’ crop choice decisions. Main results using seemingly unrelated and fixed-effects regression models for crop choice decision and crop diversification are summarized as follows. Find that weather shocks affect farmers’ crop choice decisions, but effects differ across major crop categories. For example, find that rainfall shocks increase the land share of pulses in both countries. However, rainfall shocks have a negative effect on the land share of tuber crops in Nigeria and cash crops in Uganda.