The prognosis of primary choroidal malignant melanoma (PCMM) is fatal if no early reliable diagnosis is performed. Any incisional biopsy is impossible, and diagnosis is only based on instrumental examinations. The purpose of this study is to evaluate the reliability of ultrasonography, fluorescein videoangiography (FV), indocyanine green videoangiography (ICGV), magnetic resonance (MR) and radioimmunoscintigraphy (RIS) in the diagnosis of PCMM in a series of 12 eyes in which the tumor was suspected. A presumed diagnosis of PCMM was made when a positive result was obtained with 3 or more methods. The presumed diagnosis was then compared with histological findings (true value) in 4 enucleated eyes. The sensitivity and specificity of every single method were evaluated comparing its results with the final presumed diagnosis and with the histological findings. Sensitivity and specificity of every single method have been expressed as percentage of correspondence with the presumed diagnosis. Sensitivity was 100% for ultrasonography, MR, FV, ICGV and 67% for RIS. Specificity was 92% for ultrasonography, 87% for RIS, 83% for MR and 82% for FV and ICGV. This study indicates that the ophthalmologist can obtain a good diagnostic reliability in the case of PCMM using only ultrasonography, FV and ICGV. Besides MR and RIS are important adjunctive methods to ophthalmological investigations for the diagnosis of PCMM.