Olfactory reference syndrome (ORS) has been defined as a psychiatric condition characterized by persistent preoccupation about body odour accompanied by shame, embarrassment, significant distress, avoidance behaviour and social isolation. ORS has however not been included in the Diagnostic and Statistical Manual of Mental Disorders (4th edition) (DSM-IV) and, given that its primary symptoms may be found in various other disorders, differential diagnosis can be problematic. Using an illustrative case of ORS, we propose diagnostic criteria for ORS. We also argue that ORS represents a unique cluster of symptoms that can be delineated as a separate diagnostic entity, and that ORS falls on a spectrum of social anxiety disorders that includes social anxiety disorder, taijin kyofusho, and body dysmorphic disorder.