The efficacy of currently available treatments for Hodgkin's disease (HD) has led to a substantial modification in the prognosis of this disease; nevertheless there is still a group of patients that cannot be cured with conventional treatments and who will be candidates for alternative therapy. In the present work we analysed the prognostic influence of the most relevant clinico-biological characteristics of HD in a consecutive series of 137 patients diagnosed and treated in a single institution. Univariate analyses identified six variables with significant prognostic influence, both on achieving complete remission (CR) and overall survival (OS); LDH > 320 U ml-1, age > 45 years, stages IIB, III and IV, extranodal involvement, alkaline phosphatase > 190 UI dl and ESR > 40 mm h. In addition, Hb < 12.5 gr dl-1 and abdominal disease were statistically relevant for CR while a poor performance score (ECOG > or = 2) affected a lower survival. In the multivariate analysis only LDH, age and the clinical stage retained a significant prognostic influence for achieving CR, while the two first factors above, together with performance status were the variables with independent prognostic value with respect to OS. Moreover, only LDH > 320 U ml-1 had prognostic influence in the probability of relapse and disease free survival (DFS), both in the univariate and multivariate analyses. According to the three independent factors obtained in the multivariate analysis for CR (LDH, age and stage) a predictive model was established that allows the stratification of patients into two prognostic groups: one with poor prognosis that includes patients with the three adverse prognostic factors, or two if one of them was elevated LDH, and the other with good prognosis that includes the remaining patients. This model was also able to separate two independent groups of patients with respect to OS and to DFS. In conclusion, the present study shows that LDH is one of the most important prognostic factors in HD.