Background; Complications of pregnancy and childbirth are the leading cause ofrndisability and death among women between the ages of 15-49. Attempts to predict theserncomplications before they occur have not been successful. Skilled attendance at all birthsrnis considered to be the single most critical intervention for ensuring safe motherhood.rnObjective; To assess factors associated with safe delivery service utilization amongrnmothers who gave birth during last five years preceding the survey in Sheka zone.rnMethodology; A cross sectional community based survey supplemented by qualitativerndesign was conducted in Sheka Zone from February to March 2008. A multistagernsampling technique was used to select the sample of 554 women. Data were collectedrnthrough structured pre-tested and semi structured questionnaires and checklist. The datarnwere entered in to Epinfo version 3.3 and analyzed on SPSS version 13 computerrnsoftware. A univirate, bivirate and multivariate analyses were done using frequencies, x2rnand binary logistic regressions respectively. The study was conducted after approval ofrnInstitutional Review Board of Medical faculty, Addis Ababa University and informedrnverbal consent was taken from study participants.rnResult; The study revealed that womenâ€™s educational status, birth order, prenatal carernuse, previous delivery at health facility and birth complication encounter during laborrnwere independent predictors of maternal utilization of safe delivery service. Mothers whorncompleted at least secondary school were more likely to give birth at health facility thanrnthose uneducated (AOR= 3.26, 95% CI= 1.51-7.06). Women with birth order above fourrnwere less likely to give birth at a health facility than those with first order births AOR=rn0.21, 95%CI= 0.10-0.43. Women who had encountered problems in their immediate birthrnand received prenatal care were more likely to give birth at health facilities AOR= 33.78rn95% CI=16.44.-69.39) and (AOR= 2.55, 95% CI= 1.05 6.21) respectively.rnxirnConclusion; Factors affecting safe delivery service utilization are related to the userrn(women) and provider (health system) those are interrelated to each other. Consequentlyrnwomen empowerment, promotion of maternal education, prenatal care utilization,rninformation education and communication on obstetric risks and general health servicernexpansion were recommended.