[en] From 1972 to 1981 350 patients with malignant melanoma of the lower extremity underwent unilateral or bilateral endolymphatic radionuclide therapy after generous excision of the primary tumor. Unilateral treatment consisted in 0.5 mCi 131-I-triolein and 5 mCi 32-P-tri-n-octyl-phosphate administered as radioactively labeled Lipiodol UF, and X-ray contrast. For bilateral treatment 0.5 mCi 131-I and 2 mCi 32-P were applied in 3.5 ml of Lipiodol UF on each side. Applications, dosimetry and follow-ups were standardized. High-dosage intralymphatic radiotherapy serves the purpose of destroying 'micrometastases' which must be expected to be present in 25 to 38% of clinically normal lymph nodes even in stage I malignant melanoma. Treatment with a radioactively labelled radiopaque substance simultaneously offers diagnostic information. As the penetration of 32-P beta emissions is limited, adequate treatment is confined to metastases of less than 4 mm in size. If lymphography shows larger metastases, lymphadenectomy is inevitable. In a first series of 160 patients with stage I disease the 5-year-survival rate was 72%. Data are compared with those of other treatment modalities employed in malignant melanoma, e.g. lymphadenectomy, immunotherapy and isolated limb perfusion with cytostatics. (Author)