Background: Iron and folic acid supplementation (IFAS) is a key intervention for prevention and control of anemia during pregnancy. In Ethiopia, 24% of reproductive age women and 35.5% of pregnant women are estimated to be anemic. Although, iron folic acid supplementation is the recommended strategies for successful reduction of anemia and neural tube defect, the evidence of how much of the pregnant mothers know and unitize the supplementation is scare even in big cities including Bahir Dar. Objectives: To assess and identify factors associated with knowledge, attitude, and practice regarding iron and folic acid supplementation among pregnant women in Bahir Dar city, North west, Ethiopia. Methods: An institution based cross-sectional study was conducted from March 30 to April 30, 2020 among 400 pregnant mothers in governmental health facilities of Bahir Dr city. The study participants were selected by using systematic random sampling technique and data was collected through face to face interview. The data was entered using Epi data version 3.1 and analysis was done by SPSS version 20. Bi-variate and multi-variable binary logistic regression analysis was used. P value ≤0.05 was used to declare statistical significance. Associations between outcome and exposure variables were expressed by adjusted odds ratio with 95% confidence interval (CI). Result: Of the total of 411 respondents, study participants were included in the study with the response rate of 97.3%. Among those, (54.8%) were in the age group of <-30 years. Regarding the knowledge, attitude and practice pregnant mothers iron, folic acid supplementation, 69.5% have good knowledge, (59.3% have positive attitude) and (70% have good practice). Participants who had no educational level were almost 9 times more likely to have negative attitude relative to those who have diploma and above educational level [AOR= 8.531; 95% CI (2.343, 31.061)].Women's diagnosed as anemia were 3.92( AOR 3.92, CI: 2.4,5.47) times more likely to have good practiced for IFAs than counterparts. Conclusion and recommendation: This study showed that pregnant women in Bahir Dar city has good knowledge, positive attitude and good practice of pregnant mothers on folic acid supplementation during pregnancy. Those factors associated with knowledge, xii attitude and practice on folic acid and iron supplementation were current status of anemia, age, educational status and income level. Improve ANC service and health education on the importance of folic acid and iron supplementation is essential to increase knowledge, attitude and practice of mothers to take iron folic acid supplementation during their pregnancy.