The behavioral treatment most commonly used in the treatment of specific fears and phobias involves systematic exposure to fear- provoking stimuli. Despite being an effective treatment, some of the effects of exposure treatment may be temporary in that fear may return with the passage of time. To date, researchers have found little consistent support for any one factor as a reliable predictor of return of fear (e.g., pre-treatment fear levels, treatment duration). Within the last decade, researchers have examined the effects of context on return of fear in non-primates, and found that similarity across extinction and testing contexts minimizes fear recovery. Preliminary research from this laboratory provided only weak support for the idea that contextual factors influence return of fear, possibly because the experimental contexts were not sufficiently varied. The purpose of the present study is to examine whether spider phobics treated and followed-up in the same context have less return of fear than spider phobics treated and followed-up in different contexts. To ensure a reliable and externally valid context manipulation, contexts will consist of a standard clinical context and a natural environment context. It is hypothesized that participants will exhibit a greater return of fear when tested in a different versus familiar context at follow- up. Moreover, because research on fear and anxiety suggests that perceptions of safety, danger, control, and predictability influence fear responding, we anticipate that these perceptions will also influence return of fear. Overall, this study may provide important information about the conditions under which contextual factors affect return of fear.