Mother to child transmission of HIV (MTCT) is the major source of HIV infection amongrnchildren under the age of 15 years. This can occur during pregnancy, labour and delivery, orrnbreast/eeding. Interventions to prevent mother-to-child transmission of the HIV virus (PMTCT)rnare now an important part of HIVIAIDS reduction programs worldwide. In Ethiopia thernPMTCT program was first launched in 2003 and is being scaled up across the country. ThernP MTCT program was launched in Addis Ababa in 2004 with an opt-in approach then shifted inrnto an opt-out approach since August 2006. The objective of this study is to assess willing tornutilize the PMTCT services and to identify determinants of the PMTCT service utilization inrnAddis Ababa, Ethiopia. A cross-sectional study which employed both quantitative andrnqualitative data collection method was conducted from March to April 2010 in Addis Ababarnfrom the selected hospitals. For the quantitative section, a standardized questionnaire wasrnprepared while Focus Group Discussions (FGDs) and key informants interview werernconducted to collect qualitative data. A total of 650 pregnant women in five hospitals in therncity participated in the study. The collected data were edited, entered, cleaned and analyzedrnusing descriptive statistics and multi variate analysis with SPSS version 16. The findingrnrevealed that, the mean age of the respondents are 25.5 years, 53.1% of the respondents werernwilling to utilize the P MTCT service. The reasons given by the pregnant women for not willingrn10 utilize the PMTCT service were found to be; they did not believe that ARV prophylaxis isrneffective, lack of knowledge,fear of being identified as P LWHA by people, their husbands werernnot willing to utilize the P MTCT service and religiOn/cultural reasons. Around 70% hadrnenough knowledge about the PMTCT service. Regarding partners ' attitude 68.9% of thernhusband had positive attitude aboUl the utilization of the PMTCT service., 46.3% percent ofrnpregnant women who discussed with their husband about the existence of PMTCT service andrnEducational status and family monthly income were positively associated with willing to utilizernPMTCT service. Based on the above findings, women should be empowered throughrneducation, PMTCT programs should give emphasis on involvement of male partners, intensiverneducation to both pregnant women and their partners on prenatal HIV transmission,rnimprovement of health service (delivery and antenatal care) and stigma and discriminationsrnshould be addressed through strong information, education and communication.