The relationship between eating disorders, impulse control disorders and obsessive-compulsive disorder as part of a so-called ‘obsessive-compulsive spectrum’ is discussed, with particular emphasis on the relationship between eating disorders (particularly bulimia) and obsessive-compulsive disorder. The empirical studies on comorbidity, personality and familiarity are briefly reviewed. Both similarities and differences found in personality, body image, mental rumination, fears, physical exercises, rituals, impulses (bulimic binging and obsessive impulses) and purging behaviors of these patients are discussed from a psychopathological point of view. In particular the importance of distinguishing between obsessive thoughts and prevalent (dominant) thoughts is underlined; the distinctions between repetitive weight controls, physical exercises and purging behaviors of eating disorder patients on the one hand and compulsions on the other, and the distinction between binge impulses and obsessive impulses, are also stressed.