Protein retention, realised during pregnancy and assessed by means of the slaughter technique, was investigated in a group of eleven gilts. They were compared to a control group of littermates analysed at the mating of the first group, and to a third group of non-pregnant (NP) sisters, slaughtered together with the pregnant (P) gilts near parturition (111 days of pregnancy). The digestible crude protein (d.c.p.) supply was the same for P and NP gilts and amounted to 123 g/day during days 0–60 of pregnancy, 170 g/day during days 61–90 and 260 g/day during the remaining period.P-gilts retained significantly more protein (∼1 kg) than the NP-gilts, due to a higher retention (1.9 kg) in the reproductive organs and a lower retention (0.9 kg) in the maternal body. Compared to a previous experiment, a reduction of 10.2 kg in the total d.c.p. supply over the whole period resulted in a total decrease in protein deposition of only about 1 kg in both P- and NP-gilts, but the difference between P- and NP-gilts remained nearly the same.