Information on adult mortality is essentially non-existent in Ethiopia as in the rest of subSaharanrnAfrica. This nested case-control study was conducted with the aim of assessingrnsociodemographic and behavioural factors associated with adult death in Butajira, Ethiopia.rnAll deaths in the age-group 15-49 years during 1995-99 were taken as cases and unmatchedrncontrols of age 15-49 years were selected randomly from the computerized demographicrnsurveillance database. Data were collected by lay interviewers using a simpli fied verbalrnautopsy questionnaire. Crude and adjusted odds ratio with 95% confidence interval wererncalculated to determine associations. Causes of death were diagnosed using an "expertrnalgorithm" programmed into a computer.rnA total of 515 deaths and 1507 controls were interviewed. The major determinants ofrnmortality identified are age-groups 30-39 and 40-49 years (OR 2.99, 95%CI 1.91-4.71 andrnOR 4.01, 95%CI 2A9-6A6), male sex (OR 1 A6, 95%CI 1.09-1.95), living in a rural lowlandrnarea (OR 1.54, 95%CI 1.03-231), single marital status (OR 1.63, 95%CI 1.13-2.35), havingrnno educated person in the family (OR 1.91 , 95%CI 1.11-3.29), being unemployed (OR 1 AO,rn95%CI 1.01-1.82), and poor and very poor perceived economic status (OR 1.97, 95%CIrnIJ 1-2.94 and OR 2.98, 95%CI 173-5.13). The major causes of death observed were acuternfebri le illnesses (25.2%), liver diseases (11.3%), diarrhoeal diseases (11.1 %), tuberculosisrn(9.7%) and HIY/AIDS (7A%). Communicable diseases accounted for 60.8% of the deaths.rnThe factors associated with mortality and the high level of mortality from communicablerndiseases reflect the poor socioeconomic development of the country and inadequate coveragernVIrnas a whole in education, health and poverty allevi ation . Therefore, eff0I1s should be directedrnat planning and implementing cost-effective interventions to decrease morbidity and mortalityrnparticularly from communicable diseases. Emphasis needs to be given also to povertyrnalleviation programmes.