We carried out a prospective clinical study from June to December 1993 at the Base Hospital in Avissawella, Sri Lanka to determine the clinical features of envenomation by the hump-nosed viper (Hypnale hypnale). Sixty-two consecutive adult patients (63% males and 37% females, with a median age of 30 years [age range 13–68 years]) admitted to the medical unit following hump-nosed viper bites were surveyed. Most (85.48%) of the patients were bitten on the feet, while 14.52% of the patients were bitten either on the hands or forearms. Most (61.29%) of the patients were bitten during the evening hours (6:00–10:00 pm). The mean time for admission to the hospital following the bite was 1.5 hr (range 0.25–13 hr). All patients had signs of local envenomation manifested by pain, swelling, and induration at the site of the bite, which was occasionally associated with local hemorrhagic blister formation (11.29%) and regional lymphadenopathy (24.19%). None of the patients had signs of systemic envenomation.