Aim : To detect the prevalence of fibroid in the first trimester of pregnancy, detect the risk factors associated with fibroid, describe the size and location of fibroid and detection of variation in prevalence of fibroid with age. Material and Method : The study will be designed to enroll 500 of pregnant women in the first trimester of pregnancy that comes to cairo univeresty Maternity hospital for antenatal care. Transabdominal ultrasonography will be scheduled for all participants, starting from the beginning of the sixth week of gestation. Presence of leiomyomas will be defined by the Muram criteria with modification to include masses of minimum diameter of 0.5 cm or more. Leiomyomata will be mapped into a uterine diagram and will be categorized by location and type. Results : in present study the prevalence of one or more leimyomata was detected in 20 cases from 500 pregnant women in the first trimester of pregnancy. The percent of single fibroid were 70% and multiple fibroid was 30%. As regarding age 20% of cases were over 35 years, when we examine patients with fibroid there were high percentage of overweight patients. The prevalence of fibroid in primigravida was 6.3% and there is trend to decrease with increasing parity. The main location of fibroid was subserous (52.5%),intramural 30%, while combined subserous&interstitial fibroids were 12.5%, submucous 5%. 27.5% of patients were fundal sites, 57.5% corporal and 15% were combined fundal& corporeal sites. Conclusions : the prevalence of one or more leiomyomata was 4% among study population of 500 pregnant women attending Kaser El-Aini Outpatient Clinic in the first trimester of pregnancy.