Background: Vitamin D deficiency has been identified as a global health problem and has affected more than 1 billion people globally especially among pregnant women. The aim of this study was to determine the effect of educational program on pregnant women' awareness regarding prevention of Vitamin D Deficiency. Research design: Quasi-experimental research design was used in this study. Setting: The study was conducted at pregnant follow up Outpatient Clinic in Maternal and Child health care Center at Benha City. Sample: Simple random sample was used. The total sample of the study was included (222) pregnant women. Tools: Two tools were used I): A structured interviewing questionnaire which consisted of four parts to assess personal characteristics, obstetric history, knowledge and reported practices II): Scale to measure attitude of the pregnant women regarding vitamin D deficiency. Results of this study showed pre-program 3.6% of study group and 4.5% of control group had good knowledge regarding vitamin D deficiency. While post program 75.7% of study group had good knowledge compared with 4.5% of the control group. Pre-program 18.0% of study group and 22.5% of control group had satisfactory practices regarding prevention of vitamin D deficiency. While post program 87.4% of study group had satisfactory practices compared with 21.6% of the control group. Pre-program 3.6% of study group and 4.5% of control group had positive attitude regarding vitamin D deficiency. While post program 73.9% of study group had positive attitude compared with 4.5% of control group. This study concluded that the educational program increase knowledge, improve practices and change attitude of study group of pregnant women regarding vitamin D deficiency. There were a statistical positive correlation between study group' total knowledge, total practices and total attitude post program implementation. The study recommended that: Continuing educational programs for the pregnant women to increase their awareness about vitamin D importance for their own health & for that of their infants.