-Fecundity was estimated for short spine thornyhead (Sebas-tolobus alascanus) and longspine thornyhead (S. altivelis) from the northeastern Pacific Ocean. Fecundity was not significantly different between shortspine thornyhead off Alaska, and the West Coast of the United States and is described by 0.0544xFL(3.978), where FL=fish fork length (cm). Fecundity was estimated for longspine thornyhead off the West Coast of the United States and is described by 0.8890xFL(3.249). Contrary to expectations for batch spawners, fecundity estimates for each species were not lower for fish collected during the spawning season compared to those collected prior to the spawning season. Stereological and grave metric fecundity estimation techniques for shortspine thornyhead provided similar results. The stereo-logical method enabled the estimation of fecund ty for samples collected earlier in ovarian development; however it could not be used for fecundity estimation in larger fish.