Sexual obsessions are common symptoms of obsessive compulsive disorder (OCD). The literal content of these obsessions superficially resembles other types of iterative sexual ideation, as seen in the paraphilias, PTSD, and normal sexual fantasy. However, their form, function, and effect on behavior vary greatly. A failure to distinguish these different categories of sexual thought can lead to confusion and iatrogenic treatment. This paper will describe the content and form of sexual obsessions, clarify salient differences between sexual obsessions and other repetitive sexual thoughts, and finally discuss ways of treating sexual obsessions when they are symptomatic of OCD