To determine the clinical significance of BCL-2 expression in Hodgkin-Reed-Sternberg (HRS) cells of classical Hodgkin disease (cHD), we correlated its expression with presenting clinical and laboratory features and failure-free survival (FFS). Eligible patients were untreated and negative for HIV-1; they had biopsy-proven cHD. BCL-2 expression was determined immunohistochemically in available pretreatment tissue biopsy specimens without knowledge of clinical outcome. Tumors were considered positive if any HRS cells expressed BCL-2. We identified 707 patients with cHD, whose median age was 30 years; 54% were men. HRS cells expressed BCL-2 in 359 (65%) of 551 nodular sclerosis, 67 (47%) of 143 mixed cellularity, and all 5 lymphocyte depletion. For all patients, the 5-year FFS was 74% versus 84% for tumors with versus without BCL-2 expression (P =.0016, by log-rank test). For the 412 patients treated with adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) or equivalent regimens, the 5-year FFS for tumors with versus without BCL-2 expression was 74% versus 88% (P =.001, by log-rank test); for the 233 patients with Ann Arbor stage I or II, FFS was 84% versus 92% (P =.04, by log-rank test); and for the 179 patients with Ann Arbor stage III or IV, FFS was 62% versus 81% (P =.006, by log-rank test). Multivariate analysis confirmed that BCL-2 expression is independently associated with inferior FFS along with age 45 or older, Ann Arbor stage IV, low serum albumin and high serum lactate dehydrogenase levels. We conclude that BCL-2 is frequently expressed by HRS cells in cHD and is associated with inferior FFS in patients treated with ABVD or equivalent regimens.