Cottonseed cake was substituted by soybean pulp in the diet of West African Dwarf (Djallonke) sheep, at the Pélébina livestock farm in the commune of Djougou, Benin, in order to assess its effect on growth and economic performances. Thirty ram lambs (120 ± 10 days old, 12.65 ± 0.16 kg body weight) were divided into three homogeneous groups of ten (12.6 ± 1, 12.6 ± 0.97, and 12.7 ± 0.85 kg body weight for R1, R2, and R3, respectively). All lambs received daily the same basal diet of 70% Panicum maximum C1 and 10% corn bran, plus either 20% cottonseed cake (R1), or 10% cottonseed cake and 10% soybean pulp (R2), or 20% soybean pulp (R3). After a 15-day adaptation period, the fattening period lasted 60 days. No difference (p > 0.05) was found between groups on the average daily weight gain (R1, 77.5, R2, 73.1, and R3, 70.2 g/day), although the dry matter intake of R3 (441 g/day/lamb) was lower (p < 0.0001) than that of R1 (482 g/day/lamb). The R3 diet generated a higher net margin (6042 FCFA) than R1 (5613 FCFA) and R2 (5728 FCFA) diets.