Cell adhesion molecules are cell surface glycoproteins that may act as mediators in the metastatic process. In this study we measured serum levels of the soluble intercellular adhesion molecule-1 (sICAM-1) in 74 patients with various tumours, divided into four groups according to tumour stage and previous therapy. Serum values of sgp130 were determined in the same patients. As controls we took healthy persons (n=18 for sICAM-1; n=28 for sgp130). Two parameters were determined by ELISA. The serum values of sICAM-1 were significantly elevated compared to controls in stages III + IV both without and after previous chemo/radiotherapy (P<0.05). In stages I + II without or with previous therapy there was no significance. The serum values of sgp130 were increased significantly at each tumour stage both without and after therapy. There were significant correlations between the values of sICAM-1 and sgp130 in patients with progression (tumour stage III + IV without therapy P<0.01; after chemo/radiotherapy P<0.05). To our knowledge this relationship between the two serum parameters has never before been reported. The simultaneous measurement of sICAM-1 and sgp130 could be important in the evaluation of the clinical progression of malignant diseases.