Introduction: According to 2011 Ethiopian demographic health surveys the national and Amhara Region adult HIV prevalence was 1.5 % and 2.2% respectively. The major causes of morbidity and mortality of PLWHA (people living with HIV/AIDS) patients are OIs (opportunistic infections) that would occur in up to 40% of PLWHA. OIs are repeatedly happening in HIV (Human Immunodeficiency Virus) infected patients though there is no prior local evidence on time gap of repetition. Therefore the current study is aimed to determine time gap between repeated re-happening OIs and its associated factors among PLWHA who are initiated ART (Anti-Retroviral Treatment) Method: Institution based retrospective cohort study was conducted among 364 systematically selected PLWHA commencing ART. Time-gap was estimated using Kaplan-meier survival and actuarial life table. Hazard rate was calculated using Cox proportional-hazard model. Result: during follow up OIs were re-diagnosed in about three quarter (76.9%) of participants. In each week the probability of getting the re-happened OI was 1.1 per 100 persons. The median duration of staying free of OI re-happening was 66 weeks. In multivariate logistic regression, educational status, marital status, Prophylaxisis exposure, ART and Prophylaxisis drug adherence, hemoglobin and CD4 level were significantly associated with time gap of relapse.