While ovarian cancer is rare and screening is not recommended for most women, it is being studied as a way to reduce ovarian cancer mortality. As effective strategies for screening emerge it will be important to understand the quality of life (QOL) effects of participation in ovarian cancer screening. In this study, we examined the effects of participation in an ovarian cancer screening program on worry about cancer risk and QOL. A randomized controlled clinical trial (n = 592) was conducted. Women without a family history suggestive of a BRCA1/2 mutation were randomly assigned to screening and risk counseling, separately and in combination. Results were compared to women randomized to usual care alone. Levels of cancer worry fell for all study groups and QOL was unaffected; no statistically significant differences were found between groups. Increased levels of worry about ovarian cancer at 2-year follow-up were found among participants in screening receiving abnormal test results. For those who receive abnormal results, screening may have long-term effects and increase worry about cancer risk. Further research will be required to examine the possibility that screening reduces worry when women receive only normal, presumably reassuring, results. Copyright © 2007 John Wiley & Sons, Ltd.