Introduction: Unwanted pregnancy is one of the most important problems in family planning programs especially in developing countries. This cross-sectional study was conducted to determine the prevalence of unwanted pregnancy and factors that contributes to it's existence in ten cities in Islamic Republic of Iran.

Methods and Materials: From cases, 1548 subjects referring to the antenatal clinics of university hospitals in the following cities were included in the study: Fars, Systan and Balochestan, Hamedan, Kerman, West-Azarbayjan, Gillan, Khorasan, Khozestan, Isfahan. A face to face interview was conducted to fill out a questionnaire.

Results: The result suggests that the rate of unwanted pregnancy was reported around 34.96 percent. Familiarity with contraceptive methods was quite poor in some cities. Usage of contraceptive pills and condoms were also not correct and led to failure of the method by the rate of 12.5 percent and 8.8 percent respectively.

Conclusion: It is concluded that there is a need to plan a suitable educational plan in order to reduce the rate of the unwanted pregnancy.