During the 1975 dengue epidemic in Puerto Rico, we studied three patients who had serologically confirmed dengue with hemorrhagic manifestations. None of the patients went into shock and none died. Only one of the patients had disease that resembled dengue hemorrhagic fever (DHF) as observed in Southeast Asia. This patient was a 14-year-old boy who had epistaxis, a positive tourniquet test, moderate thrombocytopenia, and significant hemoconcentration. The other two patients had hemorrhagic disease which was of clinical importance, but was not typical of DHF. These cases of dengue with hemorrhagic manifestations are the only ones known to have been documented in Puerto Rico.