Tumor-associated carbohydrates have potential not only as diagnostic tools but also as specific therapeutic targets. Their identification, however, has been hampered by the lack of suitable technologies. We used carbohydrate array technology to compare serum antibody (IgG and IgM) levels against 37 different carbohydrates between classical Hodgkin's lymphoma (cHL) patients and age/sex-matched healthy controls. Serum IgM levels measured by ELISA against 2 of the 5 carbohydrates identified using this technique, L-α-arabinose (L-Araf) and α-N-acetylgalactosamine (GalNAc(α)), were higher (F values of 11.30 and 18.27, respectively) in a cohort of cHL patients (n = 16) than either diffuse large B-cell lymphoma patients (n = 18) or control sera (n = 12). Higher anti-L-Araf IgM levels in cHL patients were associated with cytosine arabinoside treatment (p < 0.05). The GalNAc(α) glycotope, Tn, was found to be heterogeneously expressed in the Reed-Sternberg cells of 9/20 (45%) cHL cases, but not in malignant cells of 25 cases of lymphocyte-predominant HL or another 21 hematological disorders (291 cases) examined immunohistochemically. Tn was expressed in 41/238 (17%) classical HL cases present on a tissue microarray. Expression was associated with CD79a and LMP1 expression and negatively with p27KIP1 expression (p < 0.05). Kaplan-Meier survival analysis revealed a trend towards improved relapse-free survival with Tn expression although this was not statistically significant (p = 0.271). We suggest that this technique could provide a powerful tool for identifying novel carbohydrates in other cancers. © 2006 Wiley-Liss, Inc.