Introduction: The first 48 hours after a woman has given birth is a crucial period for taking the immediate postpartum contraceptive to prevent unintended pregnancy. However many women do not realize that the time to initiate contraceptive. The postpartum period is a critical period for addressing widespread unmet needs in family planning and for reducing the risks of closely spaced pregnancies.Objective: The aim of this study was to determine immediate postpartum modern family planning utilization and associated factors among women attending delivery at Public Health Facilities in Addis Ababa.Methods: A facility based cross-sectional study design was conducted from November to December, 2019. A systematic random sampling technique was used to select the study participants. Data were entered into Epi-data version 4.6.0.0 and analyzed with STATA version 14. Data were mainly analyzed using descriptive statistic and binary logistic regression. For the qualitative study purposive sampling technique was employed, and 7 participants were interviewed. Open coded thematic content analysis was used.Result: Of the total of 586 participants, 12.97 % with 95% CI: (10.1, 15.5) mothers were used immediate postpartum contraceptive methods, of which implant was the most frequently used method. Current knowledge of IPPFP (AOR=1.79, 95% CI: (1.02, 3.24)), Attitude towards IPPFP (AOR=1.73, 95% CI: (1.05, 2.85)) and counseled at delivery room (AOR=5.85, 95% CI: (2.57, 13.14)) were associated factors for utilizing contraceptive in the immediate postpartum period.Conclusion: Utilization of immediate postpartum modern family planning was low as compared to previous study done. This study identified that factors associated with utilization of immediate postpartum modern family planning were:- mothers’ knowledge, attitude towards postpartum modern family planning and had been counseled at delivery room were identified factors may increases likelihood of immediate postpartum family planning utilization. Therefore, these factors should be emphatically considered during antenatal care and post-partum care program development and training to improve contraceptive utilize during immediate postpartum period.