Basal cell carcinoma (BCC) is the most common type of skin cancer. Ultraviolet light is the most important risk factor in lesion development and progression. Additional risk factors include exposure to arsenic, coal tar derivatives, irradiation, scars, burn sites, chronic inflammation, ulcers, and immune deficiency. BCC arises usually on sun-exposed sites such as the head and neck and occurs uncommonly on non-sunexposed sites such as the axilla, buttock, groin, penis, scrotum, vulva. The Giant BCC is defined as a lesion with more than 5 cm at its largest diameter. Especially Giant BCC on the scrotum, penis, vulva, groin, perianal area where extramammary Paget’s disease occurs commonly mimics extramammary Paget’s disease. We report a case of giant BCC in a 69-year-old man. He presented with localized pricking 6.0x6.0 cm sized erythematous patch with erosion and hyperpigmentation on the perianal area for 4 years. Histopathological findings showed basaloid tumor cells budding within upper dermis and variable infiltrate of lymphocyte, plasma cells around tumor cells. Also, palisading and basaloid cell with variable atypia aggregated in the tumor cells and stroma separates from tumor lobules. He was diagnosed with Giant BCC mimicking extramammary Paget’s disease on the perianal area and had no recurrence after complete excision.