Abstract Background: OHSS (Ovarian Hyper stimulation Syndrome) is the most serious iatrogenic complication of ovulation induction. The pathophysiology of OHSS is characterized by increased capillary permeability, leading to leakage of fluid from the vascular compartment, with third space fluid accumulation and intravascular dehydration. Objective: This study aimed to evaluate the effectiveness of Calcium dobesilate (CaD) in comparison to the dopamine agonist cabergoline in preventing OHSS in high-risk patients undergoing assisted reproductive technique cycles. Methods: In this study, 200 women who were at high risk for developing OHSS were randomly allocated into two groups. Group A (Calcium dobesilate group, 100 women) and group B (Cabergoline group, 100 women). All patients were assessed weekly after retrieval and for 8 weeks to determine early clinical or ultrasound evidence of OHSS. Results: There was a statistically significant reduction (P=0.005) in the incidence of OHSS in the Calcium dobesilate (CaD) group (12%) compared to cabergoline group (28%). The number of severe OHSS cases in the cabergoline group (n=13) was significantly higher (P=0.003) than the CaD group (n=2). There was no difference in clinical pregnancy rate. Conclusion: Our results concluded that Calcium dobesilate (CaD) was more effective in preventing severe OHSS and decreasing OHSS occurrence rates than cabergoline when used in highrisk patients.