Primary soft tissue tumours of the penis, such as leiomyomas, are very rare. Most present as small and painless but gradually increasing swellings on the penis. To the best of our knowledge, only 9 cases have been reported in the literature so far. This rare pathologic finding, which usually mimics a malignant lesion, should be included in the differential diagnosis of penile neoplasm. Surgical excision of the lesion provides both the histological diagnosis and an effective therapy. We report a case of a large leiomyoma on the shaft of the penis measuring 8x5 cm, which possibly represents the largest reported leiomyoma of the penis in English literature till date.