The studies presented in this article explored the relevance of death fears to Obsessive Compulsive Disorder (OCD). In Study 1, the relationships between death anxiety and a variety of markers of psychopathology were examined in 171 treatment-seeking participants with OCD. Moderate to large correlations between Collett-Lester Fear of Death scale scores, taken at initial assessment, and clinical ratings of OCD severity, number of hospitalizations, number of medications, and total number of lifetime anxiety-related diagnoses identified in structured diagnostic interviews were obtained. Study 2 used the mortality salience (MS) paradigm to examine whether experimentally manipulated death cognitions exacerbate compulsive cleaning behaviors among OCD washers. Treatment-seeking participants with OCD (66 washers and 66 nonwashers) were randomly allocated to either a MS or dental pain priming condition. Following priming, participants completed a series of distraction tasks involving skin conductance recording, before being offered an opportunity to wash conductive gel off their hands. As hypothesized, washers went to greater efforts in cleaning (as measured by washing duration and soap and paper towel use) than nonwashers. Similarly, participants in the MS condition showed greater cleaning than those in the dental pain salience condition. However, these main effects were qualified by significant interactions for both washing duration and soap use. As expected, simple effect contrasts revealed that the effect of MS on cleaning behaviors was significant for washers but not for nonwashers. Clinical implications and directions for future research are discussed.