If the viability and sustainability of smallholder agriculture is to be maintained and food security is to be enhanced in sub-Saharan Africa (SSA), intensified, market-oriented livestock production needs to be promoted. This paper presents empirical evidence to support this contention. Twenty-five years ago there were half as many people in SSA as there are today and population is projected to increase by 2.6 times to 1,294 million in 2050. Growing population pressure on land in combination with traditional methods of farming (little use of modern inputs and low yielding crop varieties and low productivity breeds of livestock) lead to unsustainable practices that degrade land resources. Such practices result in low per capita food output and inadequate income to acquire sufficient food to ensure food security for many small-scale farmers. Shifting cultivation and nomadic pastoralism were appropriate responses to ample land and scarce capital. Growing competition for land between crop and livestock farmers, limited access to technology and inputs, and absence of properly functioning markets then led to mixed crop-livestock farming systems as efficient and sustainable methods of food production. These traditional practices, however, are not sustainable in the face of increasing population pressure and do not make sufficient impact on food security. Major changes in the methods of production, including genetic improvement, are required. Crop improvement leads to higher yields making more food available, but does not improve farmers' access to food much since it has little impact on incomes. When yields are up, prices usually decline due to the low-income elasticity for cereals. Attention has to be shifted from food production to an emphasis on improving the purchasing power of families at risk of malnutrition. This can be accomplished through intensification of livestock activities, which increase cash incomes. More than half the population is expected to live in urban areas of SSA in 2050. Urbanisation increases demand for food of animal origin and provides an impetus for intensified, marketoriented livestock production such as using crossbreeding goats or cattle for dairy and/or meat production. Theory distinguishes two types of food insecurity - chronic and transitory. Market-oriented livestock activities have potential to improve both chronic and transitory food insecurity by providing more food, by raising purchasing power (via higher incomes from sales of livestock products) and by improving the stability of both production and income to ensure availability and access to food.