The ewes requirments for energy and protein increase rapidly during the last two months of pregnancy and particularly in the final few weeks. A major limitation to the use of changes in liveweight or condition score as indices of the adequacy of nutrition during late pregnancy is that they provide information only in hindsight. By the time an inadequate weight gain or an excessive loss of condition has been recognised an irreparable production penalty may have been incurred. A more immediate assessment of the adequacy of contemporary nutrition is afforded by the measurement of circulating concentrations of certain blood metabolites. The objective of this experiment was to compare the effects of seven dietary treatments in ewes carrying twins on the pattern of plasma β-hydroxy-butyrate, glucose, albumin and urea levels in the last month of pregnancy and their relationship with energy and crude protein intakes.