Using a male eating disorder (ED) sample, this study assessed the clinical utility of the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) severity indices for males with anorexia nervosa (AN) and bulimia nervosa (BN) and compared it to an alternative transdiagnostic severity categorisation based on drive for thinness (DT). The participants included 143 males with an ED (60 [42.0%] AN and 83 [58.0%] BN) diagnosis, who were classified using these two severity classifications. The different severity categories were then compared based on ED symptoms, general psychopathology, and personality traits. Our results revealed that the DSM-5 "mild" and DT "low" severity categories were most prevalent in the AN and BN male patients. Clinically significant findings were strongest for the DT categorisation for both AN and BN. The current findings provide initial support for an alternative transdiagnostic DT severity classification for males that may be more clinically meaningful than the DSM-5 severity indices.