INTRODUCTION: Mortality among HIV-positive adults awaiting antiretroviral therapy (ART) has previously been found to be high. Here, we compare adolescent pre-ART mortality to that of adults in a public sector HIV care programme in Bulawayo, Zimbabwe. METHODS: In this retrospective cohort study, we compared adolescent pre-ART outcomes with those of adults enrolled for HIV care in the same clinic. Adolescents were defined as those aged 10-19 at the time of registration. Comparisons of means and proportions were carried out using two-tailed sample t-tests and chi-square tests respectively, for normally distributed data, and the Mann-Whitney U-tests for non-normally distributed data. Loss to follow-up (LTFU) was defined as missing a scheduled appointment by three or more months. RESULTS: Between 2004 and 2010, 1382 of 1628 adolescents and 7557 of 11,106 adults who registered for HIV care met the eligibility criteria for ART. Adolescents registered at a more advanced disease stage than did adults (83% vs. 73% WHO stage III/IV, respectively, p<0.001), and the median time to ART initiation was longer for adolescents than for adults [21 (10-55) days vs. 15 (7-42) days, p<0.001]. Among the 138 adolescents and 942 adults who never commenced ART, 39 (28%) of adolescents and 135 (14%) of adults died, the remainder being LTFU. Mortality among treatment-eligible adolescents awaiting ART was significantly higher than among adults (3% vs. 1.8%, respectively, p=0.004). CONCLUSIONS: Adolescents present to ART services at a later clinical stage than adults and are at an increased risk of death prior to commencing ART. Improved and innovative HIV case-finding approaches and emphasis on prompt ART initiation in adolescents are urgently needed. Following registration, defaulter tracing should be used, whether or not ART has been commenced.