A new AJCC/UICC staging classification of malignant melanoma was published in 2001 and has been in use since then. Compared to the TNM classification used for the previous 15 years, the new classification contains fundamental changes. The classification of the primary tumor is now based on newly defined classes for Breslow's tumor thickness (0 - 1.0 mm; 1.01 - 2.0 mm, 2.01 - 4.0 mm; > 4.0 mm). Histopathologically diagnosed ulceration is the second prognostic factor in primary melanoma and its presence leads to upstaging into the next higher T category. Clark level of invasion is now only relevant for tumors up to 1 mm thick; levels IV and V are also reasons for upstaging. Classification of regional lymph node metastasis distinguishes between microscopic metastasis only as detected with sentinel lymph node biopsy and clinically detectable macroscopic metastasis. Additionally, the number of metastatic nodes and the presence of satellite and in-transit metastasis are prognostic factors for classification of regional lymph node metastasis. In distant metastasis, the kind of organ involvement has a role for classification (only skin and lymph nodes vs. lung vs. other organs) and an elevated LDH value leads to upstaging. A critical analysis of data of the German Central Malignant Melanoma Registry did not confirm the strong role of histopathological ulceration of the primary tumor in all T- and N-stages. Furthermore, there is an inconsistency of the classification as stage IIC displays a significantly worse prognosis as compared to stage IIIA. In spite of these drawbacks the new staging classification should used particularly in clinical trials in order to make data internationally comparable.