Quantitative expressions are presented describing the potential reproductive rate per individual female of <i>Pseudocalanus</i> spp. in several different waters (not reduced by food limitation) as a function of both temperature and cephalothorax length of females (one equation for each studied region). The calculations were made for some geographically separate populations of <i>Pseudocalanus</i> spp. from southwest Baffin Island, Nova Scotia, Long Island Sound, Scotland, as well as the southern North Sea and its adjacent waters (e.g. the English Channel). On the basis of the findings presented in this work and from other studies, the reproductive rate was computed as the mean number of eggs per sac divided by 1.25 times the embryonic duration at the given temperature. Also computed was the amount of egg matter produced per day as a percentage of body carbon (and dry weight) of female weight for all localities. The relationships for females from the southern North Sea were obtained for "viable eggs", but they should be treated with reserve. A more suitable expression describing egg production in the southern North Sea is the equation for females from the English Channel obtained here. Our assumptions and approximations appear to predict quite well the temperature-length of female dependent daily rates of egg production of well-fed females of <i>Pseudocalanus</i> spp. for the above waters, and we suggest that they can be used to test the hypothesis more thoroughly.