Cohorts describing cause specific mortality in HIV-infected patients initiating antiretroviral therapy (ART) operate on an outpatient basis. Hospitalized patients represent the spectrum and burden of severe morbidity and mortality in patients on ART. To determine the causes and outcomes of hospitalization among adults receiving ART. A prospective cohort study. We enrolled 201 participants (50% female) with median (IQR) age and CD4 count of 34 (28-40) years and 91(29-211) cells/uL respectively. The most frequent causes of hospitalization were tuberculosis (TB) (37, 18%), cryptococcal meningitis (22, 11%), zidovudine (AZT) - associated anemia (19, 10%), sepsis (10, 5%) and Kaposi's sarcoma (10, 5%). Forty two patients (21%) died: 10 (24%) had TB, 8 (19%) had cryptococcal meningitis and 5 (12%) had sepsis, 9 (21%) had undiagnosed neurological syndromes while 10 (24%) had other illnesses. Predictors of death included low Karnofsky performance score of < 40 (OR, 21.1; CI 1.43- 31.6) and age >34 years (OR, 7.65; CI 1.09- 53.8). Opportunistic infections, malignancy and AZT-associated anemia contributed to most hospitalizations and mortality. It is important to intensify prevention, screening, and treatment for these opportunistic diseases and early ART initiation in HIV-infected patients. Tenofovir-based regimens, unless contraindicated should be scaled up to replace AZT-based regimens as first line ART drugs.