No experimental evidence exists on the biological advantages of frequent or maximum reproduction compared to lower or optimal levels of reproduction. Twenty unrelated rats, divided into two groups, were thus used in the biological comparison between optimum and maximum reproduction. No difference between the two systems was found in terms of feed required/biomass (cumulative litter mass plus female mass). This experiment, therefore, indicates that maximum reproduction is not necessarily more efficient in a biological sense than optimum reproduction and that experimental evidence is needed to support the contention that frequent reproduction is the best approach to increasing biological efficiency.