Sub-Saharan Africa (SSA) continues to experience food insecurity underpinned by low crop productivity. Yields for cereal crops in smallholder farming systems are typically less than 30% of attainable yields and low use of fertilizer and other nutrient resources are recognized as the one of the major limiting factors. Improved crop nutrition depends fundamentally on optimizing soil health. This chapter review the principles and use of integrated soil fertility management (ISFM) as a path towards sustainable intensification. It addresses the challenges of improving uptake and accounting for the huge variability in smallholder systems.