In this study, we estimate an output distance function in the context of a multi-output and multi-input production technology by stochastic frontier techniques. Unbalanced panel data for smallholder farms that grown cassava and other crops in Southwestern Nigeria covering 2006/07 to 2008/09 farming seasons is used for the analysis. The results show that the marginal rate of transformation (MRT) between “other crops” grown by the farmers and cassava produced relative to the output mix is negative and significantly different from zero. We observed also that increasing returns-to-scale as well as technical progress characterized cassava production in the region. Furthermore, fertilizer and pesticides are found to have significant substitution effects on cassava production in the sample. We also found evidence that, in pairs, farm size and pesticides, labour and fertilizer as well as fertilizer and pesticides jointly exhibit significant complementary effects on cassava production in the region. An average technical efficiency level of 72.1 percent which implies approximately a 39 percent inefficiency level is observed from the study. Over the seasons, we found significant evidence of an increasing trend in technical efficiency level of the farms. Extension, credit and, occupation (i.e., full time farming) are indentified as efficiency increasing policy variables from the study.