BackgroundAntenatal care (ANC) is a care given for pregnant women and is a good opportunity to deliver maternal health interventions. Even though pregnant women should start their first antenatal care within 12 weeks of gestational age, many pregnant women start their first ANC late. So, the aim of this study is to determine magnitude of late ANC booking at first visit and factors associated with it.MethodsInstitutional based cross sectional study design was conducted in central zone of Tigray Region, Ethiopia from November 1/2017 to January 30/2018 among total of 632 pregnant women. Stratified multi stage cluster sampling method was used to select health centers and systematic random sampling technique was used during the selection of study units. Data were collected using interview administer questionnaire by face to face. The collected data were entered into EPI info-7. Later on, it was exported to STATA-14 for further analysis. Proportion was used to estimate the magnitude of late ANC booking. Bivariable and multivariable analysis were done to see factors associated with the magnitude of late ANC booking.ResultsThe magnitude of late ANC booking at first visit were 85.67% (95%, CI: 82.89, 88.45). Factors that were independently associated with the late ANC booking at first visit in multivariable analysis were; having home delivery in previous delivery (AOR = 2.2, 95%, CI: 1.1, 4.49), women who had no previous ANC follow up (AOR = 3.43, 95%, CI: 1.32, 8.92) and women with poor knowledge about the advantage and service availability of ANC (AOR = 3.9, 95%, CI: 1.83, 8.29).ConclusionIn summary, most of pregnant women were not started their first ANC at the recommended time. Home delivery and history of ANC in previous pregnancy as well as women with poor knowledge about ANC were associated with late ANC booking at first visit. Health workers should work on avoiding home delivery and increasing the knowledge of pregnant women on ANC may help on reducing late ANC booking at first visit.