The identification of recurring chromosomal translocations has provided clues to the gene regions important in lymphoma development. Among 157 patients with non-Hodgkin lymphoma studied by cytogenetic analysis, four new recurring translocations have been identified--t(8;9) (q24;p13), t(11;18)(q21;q21), t(14,15)(q32;q15), and an unbalanced translocation giving rise to der(22)t(17;22) (q11;p11). Each translocation appeared twice. The t(11;18) was the only karyotypic abnormality in the two patients with it, and the t(14;15) was the sole karyotypic abnormality in one patient. All translocations were found in B-cell malignancies and were associated with both nodal and extranodal disease. Among the regions affected, only the immunoglobulin heavy-chain gene MYC, and BCL2, have thus far been associated with lymphoma. The breakpoint sites identified by these translocations warrant further investigation at the molecular level.