BACKGROUND: In sub-Saharan Africa, early mortality is high following initiation of antiretroviral therapy (ART). We investigated 6-month outcomes and factors associated with mortality in HIV-infected adults being assessed for ART initiation and presenting with weight loss, chronic fever or diarrhea, and with negative TB sputum microscopy. METHODS: A prospective cohort study was conducted in Malawi, investigating mortality in relation to ART uptake, microbiological findings and treatment of opportunistic infection (OIs), 6 months after meeting ART eligibility criteria. RESULTS: Of 469 consecutive adults eligible for ART, 74(16%) died within 6 months of enrolment, at a median of 41 days (IQR 20-81). 370(79%) started ART at a median time of 18 days (IQR 7-40) after enrolment. Six-month case-fatality rates were higher in patients with OIs; 25/121(21%) in confirmed/clinical TB and 10/50(20%) with blood stream infection (BSI) compared to 41/308(13%) in patients with no infection identified. Median TB treatment start was 27 days (IQR 17-65) after enrolment and mortality [8 deaths (44%)] was significantly higher among 18 culture-positive patients with delayed TB diagnosis compared to patients diagnosed clinically and treated promptly with subsequent culture confirmation [6/34 (18%);p = 0.04]. Adjusted multivariable analysis, excluding deaths in the first 21 days, showed weight loss >10%, low CD4 count, severe anemia, laboratory-only TB diagnosis, and not initiating ART to be independently associated with increased risk of death. CONCLUSIONS: Mortality remains high among chronically ill patients eligible for ART. Prompt initiation of ART is vital: more than half of deaths were among patients who never started ART. Diagnostic and treatment delay for TB was strongly associated with risk of death. More than half of deaths occurred without identification of a specific infection. ART programmes need access to rapid point-of-care-diagnostic tools for OIs. The role of early empiric OI treatment in this population requires further evaluation in clinical trials.