Three cases of glans penis epidermoid carcinoma after lichen sclerosus et atrophicus (LSA) or balanitis xerotica obliterans are discussed. Relationships between both diseases are analyzed but remain unclear. Balanitis xerotica obliterans causes foreskin and urethral meatus stenosis that requires circumcision. Gians penis carcinoma can be observed many years later even after circumcision. The knowledge of LSA is important to do circumcision at the beginning of the disease with a long-term follow-up of these patients to realize a glans penis biopsy if necessary. Most cases of LSA are not recognized, and the frequency is higher than reported.