Utilization review and other managed care techniques require that health care professionals assume new responsibilities as patient advocates. This article explores the extent to which characteristics of providers or their experiences with managed care practices predict the nature and extent of advocacy behavior. Interviews of 142 mental health providers revealed that experiences of harmful utilization review and norms of professionalism significantly predicted advocacy behavior. However, providers who were concerned about disaffiliation were less likely to challenge the plan directly but more likely to alter their presentation of the case to reviewers. Providers who believe that managed care plans retaliate against advocacy behavior appear to substitute covert advocacy for direct advocacy. These results are preliminary but suggest that providers condition their advocacy behavior in response to their experiences with and perceptions of managed care plans.