Polycystic ovarian syndrome (PCOS) is the most common cause of anovulatory infertility and is responsible for 70% of infertility due to anovulation . The first line of treatment is usually clomiphene citrate and it induces ovulation in approximately 80% of the patients although the pregnancy rate is only about 35–40%. If patients fail to respond in terms of ovulation to a dosage of 150 mg/day, they are considered as clomiphene resistant. Laparoscopic ovarian drilling has been widely established as an elective second line method of ovulation induction in CC-resistant PCOS patients with high ovulation (80%) and pregnancy rate (60–80 %). Advantages of LOD include less complication rate less time needed for cycle monitoring and the low risk of multiple pregnancies.The surgical approach is not associated with ovarian hyperstimulation and can lead to consecutive ovulation without the need for further treatment. However, tubo-ovarian adhesions and theoretical risk of premature ovarian failure (POF) following LOD may occur. Therefore, the role of treating only one ovary, minimising the number of diathermy points in reducing future tubo-ovarian adhesions has been studied recently. In this study 60 patients of PCOS were recruited from outpatient clinic of Zagazig University hospital. Preoperative hormonal profile was done for all the patients: FSH, LH and serum progesterone. All patients were randomly allocated to either unilateral (group I=30 patients) or bilateral laparoscopic ovarian drilling (group II=30 patients).There was no statistical significant difference between two groups as regard age, duration of infertility and menstrual pattern. Also there was no statistical significant difference between two groups as regard hormonal levels. After the laparoscopy, 21 patients in group I (70%) regained regular cycles after unilateral ovarian drilling , 6 patients were having oligohypomenorrhea and 3 patients were having amenorrhea while in group II, 23 patients (76.67%) regained regular cycles after bilateral ovarian drilling , 5 patients were having oligohypomenorrhea and 2 patients were having amenorrhea . There was no statistical significant difference between the 2 groups as regards difference in clinical outcome in terms of regular cycles, (P>0.05).After unilateral ovarian diathermy, there was an increase in serum FSH with a statistical significant difference .Also there was a decrease in serum LH after laparscopy with a high statistical significant difference. As regards the serum progesterone, there was a high statistical increase in serum levels after unilateral ovarian diathermy. After bilateral ovarian diathermy, there was an increase in serum FSH with a high statistical significant difference .Also there was a decrease in serum LH after laparscopy with a high statistical significant difference. As regards the serum progesterone, there was a high statistical increase in serum levels after bilateral ovarian diathermy.In the present study, the mean of the postoperative serum LH level of group I was 5.8±1.69mIU/ml and that of group II was 5.7±1.4mIU/ml with no statistically significant difference between the 2 groups.The mean level of serum postoperative FSH in group I was 6.89±1.3 mIU/ml and that of group II was 7.01±1.6 mIU/ml. Thus this study demonstrates that there is an increase in FSH level in both groups after LOD with no statistically significant difference between the 2 groups. The mean level of postoperative serum progesterone of group I was 4.6±1.2 ng/ml and that of group II was 4.3±1.16 ng/ml. No statistical significant difference was found between the two groups. So in this study no statistically significant difference was found between the 2 groups as regards overall clinical response (restoration of regularity of menses) and ovulation rate. In conclusion, laparoscopic ovarian drilling is an alternative modality of treatment in clomiphene resistant PCOS, and that Unilateral drilling cauterization of the ovary is equally efficacious as bilateral drilling in inducing ovulation.