Background: Antenatal care is concerned mainly about preventive, early diagnosis andrntreatment of general medical and pregnancy associated disorders. For it to meaningful, timelyrninitiation is recommended. However, late entry to antenatal care is still a major problem.rnPregnant women who do not have timely and appropriate care would be ill-equipped to makernchoices that will contribute to their own well-being. Assessment of magnitude and factorsrnaffecting late initiation of antenatal care among pregnant women in antenatal clinics is helpfulrnfor future planning.rnObjective: To assess the magnitude and factors affecting late initiation of antenatal care servicernutilization among pregnant women who attended antenatal care clinics in Mekelle townrngovernmental health institutions during the study period.rnMethodology: Across sectional facility based study was conducted in Mekelle town fromrnFebruary 1, to March 1, 2010 on 419 pregnant women attending antenatal care at governmentrnhealth institutions. Data collection tools were adopted from different literatures, modified to thernlocal context and pre-tested. Face-to-face interview of women were done by trained Nurses.rnConsecutive sampling technique was employed to select the study subjects. Bivariate analysisrnwas employed to see the association between variables and the final model was constructed usingrnstepwise logistic regression selection method. Ethical clearance was obtained from Ethicalrncommittee of Addis Ababa University School of Public health office before starting datarncollection.rnResults: Mean ages of the respondents were 26.2 + 5.4 years. Prevalence of late entry tornantenatal care was 64.7%. The timing of antenatal care booking ranges from 1st month to 8thrnmonths of gestation. The median timing was 4 months (SD 1.6). Multivariate analysis revealedrnthat respondents age, educational status, knowledge on the benefit of ANC to child health,rnwantedness of pregnancy, and recommended gestational age to start ANC (OR= 0.12, 95% CI:rn0.34,0.39),(OR=0.12,95%CI:0.34,0.39),(OR=4.65,95%CI:1.04,20.75),(OR=2.61,95%CI:1.00,rn6.77), and (OR=27.49, 95%CI:9.49, 79.64),respectively were found to be independent predictorsrnof initiation time of antenatal care service utilization.rnConclusion:- Late booking is still a major problem in this part of the study area. Public healthrneducation and reducing unwanted pregnancy would be helpful in reducing the problem.