Background: Exclusive breastfeeding (EBF) has the potential to significantly reduce infantrnmortality, but is frequently not practiced in low-income settings where infants are vulnerable tornmalnutrition and infections including human immunodeficiency virus (HIV).rnObjective: This study is intended to assess factors influencing adherence to exclusively breastrnfeeding (EBF) among HIV positive mothers, in selected health institutions of Addis Ababa.rnMethods: Facility based cross-sectional, study design supplemented by qualitative method wasrnconducted among 384 HIV positive mothers drawn from purposively selected 3 hospitals and 10rnhealth centers with ART and PMTCT service in Addis Ababa City from Jan 1to Feb30, 2012.rnData were collected using pre-tested structured questionnaire and entered into a computer andrnanalyzed in SPSS software version 16.rnResults: The prevalence of EBF adherence and non adherence were (73.0%) and (27.0%)respectively. Among mothers who did not adhere to EBF, the commonest reasons mentionedrnwere family opposition (44.0%) and (19.0%)due to infant illness. The major predictors for EBFrnadherence included ANC follow up four or more times (AOR=1.89; 95%CI=1.05-3.43), hadrnnegative attitude towards EBF (AOR=0.32; 95%CI=0.16-0.63) and maternal illnessesrn(AOR=0.27; 95%CI=0.14-0.53).rnConclusions and recommendations: Although the majority of mothers adhered tornexclusively breast feeding, still more actions are needed. Therefore, it is recommended tornstrengthen and widen the MSG (mother support group)in each health facility that focuses on thernimportance of ANC follow-up. Other important actions are to change the negative attitude ofrnmothers towards EBF through BCC and furthermore advise mothers to get a timely treatmentrnwhenever they experience illness.