Immunoscintigraphy (IS) with 99Tcm-labelled anti-melanoma monoclonal antibody F(ab')2 fragments was performed in 135 melanoma patients, 64 males and 71 females, aged 19-82 years (mean 52.3 years) between December 1987 and December 1991. The first group of IS was performed in 50 patients before surgery to assess optimal management: seven true positive and one true negative were obtained in ocular and visceral melanomas, while in cutaneous MM sensitivity, specificity and accuracy in assessing lymph node involvement were, respectively, 61.5, 93.3 and 83.7%. The second group of 128 IS is relative to 85 patients in follow-up: excluding 13 cases with known metastatic disease and 12 inconclusive tests, sensitivity, specificity and accuracy were, respectively, 83.3, 98.8 and 96.1%. Immunoscintigraphy is free of side effects even after repeated administrations and is a useful adjunct to standard diagnostic techniques as a basis for treatment decisions.