We assessed CD30 expression in patients with acute lymphoblastic leukemia (ALL) of either T-cell or B-cell lineage to examine the potential benefit of anti-CD30-targeted therapy in this group of patients. Bone marrow specimens of 34 patients with T- and 44 with B-ALL were assessed for CD30 expression by multicolor flow cytometry immunophenotyping analysis. Of these 78 patients, 75 (96%) were adults; and 63 (81%) had refractory/relapsed disease. Using an arbitrary 20% cut-off, 13/34 (38%) cases of T-ALL and 6/44 (13%) cases of B-ALL were considered to express CD30. In five patients with T-ALL with sequential bone marrow tested, increased CD30 expression was observed during the course of high-dose chemotherapy (p = 0.025). Philadelphia chromosome/BCR-ABL1 fusion was positive in 14/44 cases of B-ALL and 2/32 cases of T-ALL, which showed no significant correlation with CD30 expression. In summary, we detected CD30 expression in approximately one-third of patients with T-ALL, and less frequently in B-ALL (p = 0.017). In T-ALL, CD30 expression is up-regulated during high-dose chemotherapy. These data indicate that anti-CD30-targeted therapy may be a potential option for patients with T-ALL with refractory/relapsed disease.