Background and Aims: Ano-genital granulomatosis is a rare chronic granulomatous condition of the skin that causes lymphoedema of the external genitalia. There is a reported association with Crohn's disease. Mechanisms of disease and optimal methods of treatment are poorly understood. Methods: A retrospective casenote review of 25 male patients with ano-genital granulomatosis presenting with genital lymphoedema was performed to determine the clinical and histopathological features of this condition and its relationship to intestinal Crohn's disease. Results: A combination of penile and scrotal oedema was reported at presentation in 80% of patients; 40% of patients had associated intestinal Crohn's disease. The average time from symptom onset to diagnosis was 52.7 months. Half of cutaneous biopsies contained non-caseating granulomas and 14% contained intralymphatic granulomas. In all, 72% of patients responded to oral steroids initially but recurrence was common. Complete or partial response was achieved in 60% of patients treated with azathioprine. Three of six patients responded to anti-tumour necrosis factor [TNF] therapy. A small proportion of patients required circumcision or de-bulking surgery for more debilitating disease. Conclusions: Ano-genital granulomatosis is a rare condition that presents with genital lymphoedema, and there is frequently a protracted delay in diagnosis. There is a very strong association with intestinal Crohn's disease. Genital lymphoedema associated with gastrointestinal symptoms should prompt careful evaluation to exclude both ano-genital granulomatosis and Crohn's disease.