The Mean of the Ten Largest Nuclei (MTLN1) is one of the most important prognostic factors in uveal malignant melanoma. This study was performed to investigate the applicability of nuclear and nucleolar measurements as a prognostic factor for cutaneous melanoma. A routine light microscope (Carl Zeiss: Axiophot EL-Einnsatz; #451888) at 640 times magnification with a Micrometer Eye Piece (Carl Zeiss: #444034) was used to evaluate the correlation of MTLN1 and Mean of Ten Largest Nuclei (MTLN) with the occurrence of metastasis in 58 primary cutaneous melanoma. For uveal melanoma, cytologic classification was used for comparison. Prognostic value was determined by univariate and multivariate linear regression analysis. MTLN1 was the only significant factor for uveal melanoma (p = 0.05). For cutaneous melanoma, all factors were significantly associated with disease progression. MTLN1 was the only one to remain significant (p + 0.027) in multivariate linear regression analysis. Nuclear and nucleolar morphometry are significant prognostic factors for uveal and cutaneous melanoma.