The published literature in Australia on red-back spider-bites allows no means of determination of the incidence of this envenomation. This retrospective study describes the experience at Fremantle Hospital with red-back spider-bites over a six-year period from 1982-1987 inclusive. One hundred and fifty patients were admitted to hospital with a definite red-back spider-bite, of whom 32 (21%) patients received antivenom; 11 (34%) of these patients received more than one ampoule. In earlier series, only 3% of patients have received more than one ampoule. These results suggest that the WA red-back spider is particularly venomous, and that the annual number of definite red-back spider-bites in Australia lies between approximately 830 and 1950 cases.