The relative importance of different components of efficiency depends on whether one’s interest is biological or economic. A study of the elements of biological efficiency shows that the choice of slaughter mass has a profound effect, and that in relative terms reproductive characteristics are comparatively unimportant. The production of lean meat is shown to be improved significantly by adopting different strategies for meat production by such means as using once-bred gilts, boars rather than castrates, and very early weaning. Dietary factors are important in optimizing efficiency, particularly in establishing the nutrient requirements of very young pigs which are shown to have lysine requirements of about 1 g/MJ of digestible energy. The importance of feeding pigs as close to appetite as possible is stressed. The effect on very good and moderate genotypes by increasing feed intake is examined and in both cases shown to improve the efficiency of lean meat production. The importance of flexibility in production and in the processing industry is discussed in relation to improved efficiency.