In this paper, we analyze the factors that influence t he productivity of maize among smallholder farmers, given that unfavourable output and input market conditions throughout the 1990s have compelled smallholder farmers into unsustainable agricultural intensification. We use farm-household survey data in order to compare the productivity of smallholder maize production under integrated (ISFM) and chemicalbased soil fertility management using a normalized translog yield response model. The results indicate higher maize yield responses for integrated soil fertility management options after controlling for the intensity of fertilizer application, labour intensity, seed rate as well as land husbandry practices a s well as selected policy factors. The estimated model is highly consistent with theoretical conditions. Thus we conclude that the use of ISFM improves maize productivity, compared to the use of inorganic fertilizer only. Since most farmers in the maize-based farming systems are crowded out of the agricultural input market and can hardly afford optimal quantities of inorganic fertilizer, enhancement of ISFM is likely to increase their maize productivity. We finally highlight areas of policy support needed to enhance ISFM uptake in smallholder maize-based farming systems.