Natural reproduction of hybrid striped bass (Marone chrysops x M.saxatiUs) was documented in Lake Palestine, Texas. Electrophoresis and isoelectric focusing analysis indicated 29% of the sampled Marone spp. were non F-l hybrids. These individuals apparently resulted when F-l hybrids reproduced with white bass and/or F-l hybrids. Age analysis revealed the non F-l hybrids were from years when hybrid striped bass were not stocked.