Hodgkin's disease (HD) is increasingly being evaluated by fine-needle aspiration (FNA); however, criteria to subclassify HD into its four subtypes--nodular sclerosis (NS), mixed-cellularity (MC), lymphocyte-depleted (LD), and lymphocyte-predominant (LP)--has not been established. In order to evaluate criteria for subclassification, all FNA cases of HD obtained over a 5-yr period at Indiana University Medical Center that had confirmatory surgical biopsies were reviewed. The number of Reed-Sternberg (RS) cells was quantitated in each cytologic case and statistically analyzed by subgroup, using analysis of variance (ANOVA). LD had the highest mean (means) number of RS cells (means = 51) with NS and MC having similar means (means = 7 and 6, respectively). Only one case of LP was identified and therefore could not be analyzed statistically. Fibrosis and the presence of RS variants were qualitatively assessed and were not helpful in distinguishing the subtypes of HD. Although the quantitation of RS cells may be used to identify LD types of Hodgkin's disease, MC and NS cannot be separated reliably on this criterion alone. Although FNA can be used to diagnose HD, stage a patient, or assess efficacy of chemotherapy, subtyping of HD should still be done on histologic sections of excised lymph nodes.