ABSTRACT Female blue king crabs, Paralithodes platypus, from the Pribilof Islands, were sampled during each of four seasons to determine whether they spawn each year, as do red king crabs, P. camtschatica, or every other year, as reported for Asian blue king crabs. Based on seasonal changes in two indices of ovarian development (standardized ovary weight and mean oocyte diameter) we found the period between successive spawnings to be two years and the period of embryonic development to be 14-15 months. The fecundity of blue king crabs increases with size according to: E = 241,629-2,632,606 e–0.0280L, where E is fecundity and L is carapace length in mm. Mean length and width of new external eggs are 1.2 mm and 1.0 mm.