Weanling male and female Wistar rats were fed diets incorporating 0%, 20% and 40% Acacia colei seed flour (Leguminosae), to raise three generations of animals. Weight gain decreased with increasing levels of acacia incorporation (crude protein content 12.6%) in first generation animals. Mating, 13 weeks after weaning, resulted in 80%, 60% and 0% pregnancy in female rats, average litter size of 5 and 5.5; and survival rate of 83% and 94% by rats fed 0%, 20% and 40% acacia diets, respectively. Increasing the protein content to 18% reversed the reproductive failure in the 40% acacia group: pregnancy rate was 80%, 40% and 71%; mean litter size was 8.5, 12 and 3.8 in rats fed 0%, 20% and 40% acacia diets, respectively. Growth rate was fastest in the 0% acacia group second-generation rats after the first 64 days. Mating this second generation resulted in 82%, 70% and 83% pregnancy over two matings for animals on 0%, 20% and 40% acacia diets, respectively. Weights of reproductive and other internal organs were little affected by diet-type indicating that incorporation of acacia into rat diet would not affect reproduction except for the low quality of its protein.