We describe a case of an acute myelogenous leukemia (AML) associated with t(1;11) (q23;p15), which is a novel simple variant translocation of t(7;11)(p15;p15). The patient was a Japanese man who had a history of non-Hodgkin lymphoma (NHL) and received MACOP-B combination chemotherapy. Fifteen months after the completion of the treatment, the patient developed AML (M2), which was regarded as a therapy-related leukemia. Cytogenetic study of bone marrow cells showed t(1;11). Although he achieved complete remission by combination chemotherapy, a relapse of NHL and gastric cancer were revealed in the course of the consolidation chemotherapy for AML. The NHL was considered a histological conversion from follicular lymphoma because lymphoma cells carried t(14;18) (q32;q21) and were strongly positive for BCL2 protein. Translocation (1;11), together with AML having t(7;11) or inv(11) involving 11p15, shows that 11p15 is a common acceptor site of these chromosome aberrations and suggests the significance of the NUP98 gene located in 11p15 in therapy-related leukemia.