Although tumors on the surface of the skin are considered to be easily recognizable, neglected advanced skin neoplasms are encountered even in the 21st century. There can be numerous causes of the delay in the diagnosis: fear of the diagnosis and the treatment, becoming accustomed to a slowly growing tumor, old age, a low social milieu, and an inadequate hygienic culture are among the factors leading some people not to seek medical advice. The treatment of such advanced neoplasms is usually challenging. The therapy of neglected cases demands an individual multidisciplinary approach and teamwork. Basal cell carcinoma (BCC), the most common cutaneous tumor, usually develops in the elderly, grows slowly, and has an extremely low metastatic potential; these factors are suggesting that BCCs might well be the "ideal candidates" for neglected tumors. Five neglected advanced cases of BCC were diagnosed in our dermatological institute between 2000 and 2009. The clinical characteristics and treatment modalities of these neoplasms are discussed, together with the possible causes of the neglect.