Erythema nodosum was found on 11 out of 106 patients with Crohn's disease (10.4%), being the most common skin complication after the perianal ones. Women were affected more often than men (2.7:1) and most of the patients were above 15 and below 40 years of age. Patients with ileocolic lesions were more often affected than those with lesions confined to the small bowel. No cases of erythema nodosum were found in association with granulomatous colitis, as opposed to other authors experience. The eruption was usually related to the periods of active inflammatory bowel disease but not to the administration of salazopyrine. The morphology and evolution of the lesions was typical of erythema nodosum and joint involvement was almost constant. The differential diagnosis with other nodular eruptions that can occur in association with Crohn's disease are discussed and hypothetical common etiopathogenic factors to both Crohn's disease and erythema nodosum are briefly considered. The relevant literature is reviewed and commented upon.