BACKGROUND: In Tanzania, although the prevalence and incidence of HIV is on the decline, HIV/AIDS is still significantly associated with morbidity and mortality among hospital admissions. There have been several studies portraying different patterns of morbidity and mortality among HIV/AIDS inpatients worldwide. However these findings are not necessarily applicable to our setting. This study sought to determine the current pattern of morbidity and mortality among HIV/AIDS patients admitted in the medical department at KCMC as more people living with HIV are increasingly gaining access to Anti-retro viral therapy (ART). OBJECTIVE: The aim of this study was to determine the pattern of morbidity and mortality among HIV/AIDS patients admitted to the medical department at KCMC, Moshi Tanzania. METHODOLOGY: A cross-sectional analytical hospital based study which was conducted from September 2013 to February 2014. A structured questionnaire was administered to evaluate the socio-demographic and clinical characteristics. Relevant investigations based on clinical findings were done to establish patient’s diagnosis. The end points of hospitalization in terms of discharge or death were recorded and the diagnosis at the time of discharge or death as well as factors associated with the morbidity and mortality were documented. Data analysis was done by SPSS version 16 statistical software and chi-squared test, and multiple logistic regression were used for data analysis while a p-value of less than 0.05 was considered statistically significant. RESULTS: A total of 304 patients were enrolled in the study and the majority of them were females (57.6%) their mean age (SD) was 43.6 (13.0) years, with women significantly younger than males 42.2 (14.1) years. More than a quarter of the patients (31.9%) were newly diagnosed during admission and for the previously diagnosed patients the majority (84.5%) were on ART. Moreover, more than two thirds (69.2%) of the patients were severely immunosuppressed with CD4+ T cell count of less than 200 cells/μL. Most patients (87.5%) were either in WHO HIV/AIDS clinical stage 3 or 4 and fever was the most common (63.2%) presenting clinical feature on admission. Opportunistic infections were highly prevalent (77.7%) with tuberculosis being the most common (26%) diagnosis. The in hospital mortality rate was 35.9%, while the highest mortality rate (88.9%) was in patients diagnosed with Cryptococcus meningitis. The independent predictors of mortality were duration of hospital stay of less than 3 days, renal disease, Kaposi’s sarcoma, Cryptococcus meningitis, CNS diseases, Lymphoma and CD4+ T cell count less than 50 cells/μl. CONCLUSION: A significant proportion of HIV/AIDS patients are still diagnosed in hospital with late clinical presentation and severe immune suppression and subsequently poor prognosis, contributing to a high mortality rate among HIV/AIDS inpatients. The proportion of comorbidities appears to rise as compared to the previous studies. However, despite the roll out of ART opportunistic infections and AIDS defining malignancies are still the major causes of morbidity and mortality among HIV/AIDS inpatients at KCMC. RECOMMENDATIONS: Frequent and periodic testing for HIV should be encouraged, together with early initiation of ARVs. Clinicians in similar settings should be have high index of suspicion for opportunistic infections but should be well aware of the escalating prevalence of comorbidities in HIV infected patients.