Background: The increased sexual risk and exploitation among orphans and vulnerable childrenrnand its associated physical, psychological and social consequences is becoming a major publicrnhealth concern globally. The number of orphans has risen significantly in recent years inrnEthiopia. Understanding the magnitude of risky sexual behavior and exploring factorsrnunderpinning this behavior are pivotal to address the needs of orphan and vulnerable childrenrn(OVC) and mitigating the negative outcomes of the growing OVC population worldwide.rnHowever, there is paucity of information in this regard in Ethiopia.rnObjectives: To assess the sexual practices, exploitation and its determinant factors among OVCrnin Addis Ababa city.rnMethodology:rncommunity based cross sectional study and phenomenological qualitativernmethods was conducted from March to June 2014 in Addis Ababa, Ethiopia. Quantitative datarnwas collected from OVC who were got community based carernfrom three organizations,rnselected by systematic sampling using self administered questionnaire and phenomenologicalrnqualitative methods use focus group discussion (FGD) and interview of street children. Logisticrnregression and open code were used to analysis data.rnResult : The study participants who were double orphans were about five times more at riskyrnsexual behavior than the respondents who were maternal orphan only P=0.005, COR (95% CI)rn5.455(1.674,17.770).rnThe multivariate risk sexual behavior shows that, orphans, who were living with others (non-rnrelatives and far extended relatives) were about four times more at risky sexual behaviors thanrnthose who live with their mothers [(P=0.033, AOR (95%CI) 3.849(1.116,13.272)].rnMany street children were forced to have coercive sex with strangers and older street children.rnConclusion: About 50 (44.6%) of OVC started early sexual intercourse to get basic need andrnfollowed by 39 (34.8%) of them start to facilitating social connection in their living environment.rnAbout 96 (85.7%) of OVC did not use a condom regularly while they had sexual intercoursernwith their partner.rnSexual relationship among street children is widespread among the street groups and withrnoutsiders, multiple partnerships is common.rnObviously, these findings suggest that orphan children were at high sexual risk behavior andrnexploitation next to the death of their income earner through their lack of basic needs.rnKey words: orphan and vulnerable children, street children, risky sexual behavior, sexualrnexploitation, Addis Ababa.