The experiment was designed to determine the influence of uncertainty orientation (R. M. Sorrentino, J. C. Short, 1986) on compliance with a diagnostic health behavior. Ss (N= 155) read 1 version of an education essay on a disease and diagnostic response. Threat and efficacy information were manipulated. Consistent with protection motivation theory (R. W Rogers, 1983), uncertaintyoriented Ss sought more health-related information as threat and efficacy increased. Certaintyoriented Ss, however, sought more health-related information as threat or efficacy, but not both, increased. Individual differences were also found on adaptive measures and ineffective alternative responses.Since the early research applying drive reduction models to communications in health compliance (e.g., Hovland, Janis, & Kelley, 1953), researchers have grappled with the problem of identifying the precise message characteristics of a health appeal and the precise conditions that lead to the greatest compliance. Protection motivation theorists (Rogers, 1983) have attempted to provide a comprehensive framework to account for these issues. Although promising, support for this theory is not without its inconsistencies. It is the contention of this article that predictions from this theory can be more precise if one considers important individual differences in the way people are likely to process potentially threatening information. The important individual-difference variable is what Sorrentino and Short (1986) have called uncertainty orientation. Following a brief review of research related to protection motivation theory, the importance of this variable for the theory is discussed.