Although the native red rock crab Cancer productus is an important component of Pacific northwest nearshore communities and recreational crab fisheries, little is known about its life history. Growth in crustaceans is incremental and age classes overlap, making these investigations difficult. An array of techniques was used to estimate growth and longevity of C. productus in a marine preserve at the University of Washington Friday Harbor Laboratories. These included size-frequency distribution analysis of young crabs in their nursery habitat, growth inside cages, and mark-recapture studies. The growth rate in C. productus varies greatly, with adult males exhibiting greater molt increments and molt frequencies than females. For crabs less than 80 mm in carapace width, males and females grow at the same rate: attaining 30–65 mm carapace width at age 1, and 60–95 mm at age 2. Maximum carapace widths of males and females were 171 and 150 mm, respectively, and maximum longevity is estimated to be at least 5 and probably more, much longer than previously estimated.