Abstract Background Ovarian hyperstimulation syndrome is a potentially life threatening complication of treatment with ovulation induction medications. Aim of the study was to assess the effectiveness of structured teaching program on staff nurses knowledge and preventive measures regarding Ovarian Hyperstimulation Syndrome. Research design: A quasi-experimental research design with pre/posttests and follow up was used. Setting: the present study was carried out at Gynecology ward and Laparoscopic unite at Zagazig University hospitals. Sampling and Subject: a purposive sample of 50 nurses was recruited for this study. Tools of data collection: Tool I: a structured interview sheet. Tool II: Observational checklist for nurses regarding preventive measures of OHSS. Results; A statistically significant improvements was observed in total level of knowledge score after program implantation compared to its level before intervention, where 90.0 % of the studied nurses had poor knowledge in pretest which declined to 14.0% and 18.0% at immediately post and after one month of interventions respectively. Also statistically significant improvement was revealed in total score of good practice (88.0%) in favor of the post-test compared to (10.0%) in pretest and (78.0%) in follow up phase. Conclusion: Implementation of the structured teaching program was effective in increasing the knowledge level and utilization of preventive measures regarding OHSS. Recommendations: Implementation of structured teaching program with a learning booklet for nurses on other health center for IVF should be conducted in order to increase their level of knowledge and practice regarding Ovarian Hyperstimulation Syndrome. Keywords: Structured Teaching Program, Staff Nurses, Knowledge, Ovarian Hyper stimulation Syndrome.