The Confidential Enquiry into Perioperative Equine Fatalities (CEPEF-1) is an observational multi-institutional prospective study of recovery outcome at 7 days post operatively, as called for by Steffey (1991). Data from 6,255 general anaesthetics (February 91-March 93) were submitted confidentially by 62 clinics. The outcomes of 333 cases which were subjected to euthanasia and which were not classified 'alive' or 'died' at 7 days, were excluded from the analysis. The remaining 5922 cases were analysed to identify risk ratios (RR) between survivors and nonsurvivors for a variety of factors. These preliminary results indicate an overall death rate, for equine patients dying or being subjected to euthanasia within 7 days of a general anaesthetic because of perioperative complications, of 102/6255 (1.6%). This mortality rate decreased to 46/5220 (0.9%) when all colic surgery and delivery of foals under general anaesthesia were excluded. There was an increased risk for mares in the last trimester of pregnancy (RR = 6.4). Patients undergoing emergency abdominal procedures (colic patients and pregnant mares undergoing controlled or caesarean section delivery of foals) under general anaesthesia were at increased risk (RR = 12.9) compared to ear, nose and throat surgery. Within orthopaedic surgery, patients requiring internal fixation were at increased risk (RR = 3.2) compared to those undergoing miscellaneous orthopaedic surgery. There was no difference in risk between breeds. Patients not placed in dorsal recumbency were at reduced risk (RR = 0.3-0.5) compared to those which were in dorsal recumbency.(ABSTRACT TRUNCATED AT 250 WORDS)