The serum levels of soluble ICAM-1 (sICAM-1, sCD54) were significantly elevated (p = .0006) in patients with Hodgkin's disease (HD) (n = 101) compared to healthy controls (n = 31). Serum levels of sICAM-1 in HD correlated significantly with the presence of B-symptoms, histology and tumour burden as reflected in the Ann Arbor staging system, but not to bulky disease. sICAM-1 was compared to other serum factors claimed to be of prognostic significance in HD, including erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), deoxythymidine kinase (TK), soluble interleukin-2 receptor (sIL-2R, sCD25) and soluble CD30 (sCD30, sKi-1-antigen). Serum levels of sICAM-1 correlated positively with all of these markers. In univariate regression analyses, all but ESR correlated with disease-free survival but only sICAM-1, sIL-2R and sCD30 correlated with overall survival. In multivariate analyses only sIL-2R (as a continuous variable) added independent prognostic information in addition to age, stage and B-symptoms. sICAM-1 and sCD30 approached significance (p = 0.07 and p = 0.08, respectively) for disease-free survival. sCD30 correlated with overall survival (p = 0.03) while sICAM-1 did not. When dichotomised at optimal cut-off levels, sICAM-1 as well as sIL-2R and sCD30 added independent prognostic information for both disease-free and overall survival. Based on the present observations, it appears that sICAM-1 may be a predictor for relapse and survival in HD. Determination of serum levels of sICAM-1 (in addition to sIL-2R and sCD30) may thus be of potential value when selecting HD patients eligible for intensive therapy in clinical trials.