Background: Information on causes of adult deaths is relatively scarce in developing countries where vital registration systems are often incomplete or nonexistent and many deaths occur at home. Objective: To obtain a community based estimate of the specific causes of mortality and the burden of chronic morbidity in an urban adult population with major emphasis on determining the pattern of HIV/AIDS mortality in Addis Ababa. Method: A cross sectional quantitative study was done from Dec. 2004-Jan. 2005 on 3600 randomly selected households in Addis Ababa. An appropriate VA tool and chronic morbidity assessment questionnaire were utilized for data collection. Results: The crude death rate was 8.1 per 1000 population per year. The cause specific mortality fraction of AIDS/TB , noncommunicable disease and accidents were 44.3%, 15.3% and 11.2% respectively. Age and sex specific mortality picture of AIDS showed that at early adult age (20-29) years, females exhibited a very high death rate than their male counterpart, which is high at 29-34 years of age Seventy five percent of deaths were found to have occurred at home with health institution deaths accounting for only 21%. Hypertension, asthma, cardiac problem and psychiatric illnesses were the commonest chronic illnesses identified during the study. AIDS mortality fraction is still higher as compared to other causes of deaths in Addis Ababa. The burden of AIDS mortality is higher in the center of the city where socio-economic status is low and prostitution and sex marketing is high as compared to the outer city. Conclusion and Recommendation: The proportional mortality due to AIDS is high as compared to other causes of deaths in Addis Ababa. At early adult age females exhibited higher AIDS specific mortality rate than males for which it is high at later age. Chronic non- communicable diseases are also posing significant health problems in terms of chronic morbidity and mortality in the city. Continuation of such community-based surveillance of cause of deaths is recommended.