The cytogenetics of 151 non-Hodgkin's malignant lymphomas (NHL) was reviewed to assess the incidence of monosomies and partial deletions. The incidence of complete or partial loss of chromosomes, possibly indicating putative tumor suppressor genes, was not significant. For chromosomes 3, 11, 13, 17, and 22, these frequencies were respectively 0%, 6.6%, 5.3%, 5.2%, and 6.6%. No specific association of deletions could be established. Three patients had a rearrangement of band 1q21 associated with deletion of chromosome 13. Finally, the most frequent chromosome segment loss in NHL involves the long arm of chromosome 6 (15.2%).