Basal cell carcinoma (BCC) is the most common cancer affecting Caucasians and, due to its large size or to the poor condition of the patient, it can be difficult to treat it with conventional therapies: in these cases photodynamic therapy with methyl aminolevulinate (MAL-PDT) may represent a good option. A retrospective non-comparative follow-up study was performed to test the response of giant and large BCC to MAL-PDT. Twelve patients with 14 giant BCC (> or = 5 cm) and 5 patients with 5 large BCC (4-5 cm) were treated with MAL-PDT; they were evaluated 6 months after the end of the treatment to define the initial cure rate, and then at 12 and 36 months for the follow-up. At 6 months the initial cure rate for the 19 BCCs was 95% and at 36 months the overall long-term cure rate was 66%. The follow-up will last up to 5 years. MAL-PDT is a valid option for the treatment of giant and large BCC.