ABSTRACTrnBackground- Unintended pregnancy is an important public health issue in developed and rndeveloping countries because of its negative association with the social and health outcomes forrnmothers, children, the family and the nation. In Ethiopia, a study conducted at selected publicrnhealth centers of Addis Ababa reported that the magnitude of unintended pregnancy was 38.7%;rnthis indicates that it is one of the major reproductive health problems in the city. rnObjective-The objective of this study was to assess magnitude and factors associated withrnunintended pregnancy among women attending antenatal care at Gandi memorial hospital inrnAddis Ababa.rnMethods-A facility based cross sectional survey design using quantitative method was used tornconduct this study. Systematic random sampling technique was used to select participants for thernassessment. A total of 627 women attending antenatal care were interviewed to examine sets ofrnvariables using questionnaire. Magnitude of unintended pregnancy was determined along withrnthe corresponding 95%CI. Bivariate and multivariate logistic regressions were employed tornassess factors associated with unintended pregnancy. rnResult- Out of the total 627 pregnancies, 395(63%) were intended and 232(37%) were reportedrnto be unintended. The statistically significant independent predictors for unintended pregnancy rnfound in this study were family size and number of pregnancy. Women with family size of threernor less had 66% (AOR=0.34, 95% CI=0.13, 0.79) lower chance of having unintended pregnancyrnthan those women with family size of four or more. Those women with two or less pregnanciesrnhad 55% (AOR=0.45, 95%CI=0.21, 0.91) lower chance of having unintended pregnancy thanrnthose women with three or more pregnancies. rnConclusion- Findings of this study indicated that unintended pregnancy is one of thernreproductive health problems in the study area. Family size and number of pregnancies a woman rnhad were negative predictors of unintended pregnancy. rnRecommendation- Reproductive health programs should give emphasis on mass mediarnmessages addressing on the advantages of small family size and low number of pregnancies by rncreating the awareness of the people on family planning with full availability and accessibilityrnfamily planning methods in the health facilities.