Two adult sturgeon (Acipenser oxyrhyncIuis and A. brevirostrum) from the Hudson River exhibited ovotestes. In the former, testicular and ovarian tissues were mostly separated", in the latter, intermingled. One ovotestis of A. h rev i rostrum contained small, cyst-like structures that consisted of disorganized tissues including cartilage, bone, blood vessels, gut epithelium, and connective tissue. These teratoma-like structures may have been the result of the abnormal development of a parthenogenetic or self-fertilized egg rather than a neoplastic process. None of the abnormal growths in fishes that have been described as teratomas can be considered unequivocally as examples of a true tumor or neoplasm.