Background: The recent expansion of interest in contamination-related obsessive-compulsive disorder (OCD) has fostered the description of mental contamination and a series of experiments designed to understand associated factors. This supports a cognitive approach to the understanding and treatment of contamination-related OCD--especially when the contaminant is mental, rather than contact based. Appraisals associated with responsibility, violation, and immorality have been shown to predict mental contamination responses to an imagined negative event which included negative moral elements in the absence of imagined physical dirt. Imagined physical dirt can be a highly distressing component of contamination fear and is often used in OCD research. The aim of this study was to assess whether specific appraisals could predict mental contamination responses in the context of an imagined event involving both an immoral person and physical dirt. Methods: Female undergraduate students (N = 59) imagined experiencing a non-consensual kiss from a man described as physically dirty. Results: Consistent with predictions and with previous findings, appraisals generally accounted for significant unique variance in mental contamination indices above and beyond other predictor variables. Conclusions: Further development of assessment/treatment strategies focusing on appraisals will likely improve therapeutic outcomes for mental contamination. (Contains 2 tables.)