Humoral and cellular immunity were studied in 28 children completing conventional treatment of standard‐risk (SR) or intermediate‐risk (IR) acute lymphoblastic leukemia (ALL). Both naïve and memory B cells were most severely affected and showed slow recovery during the 2‐year follow‐up, while the T‐cell compartment showed only minor changes. Immunoglobulins and IgG subclasses, components, and antibodies against vaccine‐preventable diseases were not significantly affected. In conclusion, immune recovery after conventional chemotherapy for SR and IR ALL is marked by B‐cell depletion, but otherwise did not show any severe deficiencies in lymphocyte function.