Objective:  To identify the adverse effects of the pregnant mother€™s smoking on pregnancy outcome on both the mother and her fetus.   Methods: A prospective study was conducted, between Jan. 2005 and Jan.2006. Nine hundred patients who received prenatal care and delivered at Princess Haya Military Hospital were questioned about the habit of smoking during pregnancy and were asked to fill a questionnaire related to their current and previous pregnancies. Our patients were divided into two groups: group I: 137 smokers who used to smoke during pregnancy, group II: the control group 763 non-smokers. The two groups were subdivided into subgroups according to the age, parity, occupation, residency, number of cigarettes smoked per day and duration of smoking. Data regarding the effect of smoking during pregnancy on the mother and the fetus were compared with that to non smoking pregnant women e.g. delay fertility, spontaneous abortion, ectopic pregnancy, preterm delivery, PROM, placenta previa, abruptio placenta, low birth weight, still birth, SIDS, and congenital abnormality.   Results: The above mentioned adverse effects of smoking on both the mother and the fetus during pregnancy compared to non-smokers i.e. delay fertility, spontaneous abortion, ectopic pregnancy€¦etc were statistically significant (p<0.05). The higher adverse effects of smoking during pregnancy were reflected more on delay in conception, placenta previa, congenital abnormality, and SIDS being 13.9%, 1.5%, 4.4% and 1.5% respectively with an increase one and a half to two folds for the other fetal and maternal complication.   Conclusion: Smoking during reproductive period can contribute to both fetal and maternal complications of pregnancy. Most of the smokers do know that smoking has adverse effect on pregnancy but very few know what these adverse effects are, thus a proper counseling should be offered to smokers in their first visit to the clinic. Efforts should be exerted to stop smoking during pregnancy to prevent these hazards on both the mother and the fetus. Those who continue should be considered and addressed as high risk pregnancy.