Three new cell lines have been established from patients with malignant lymphoma utilizing a human diploid feeder layer, pooled human serum, and the chemical supplements L-cysteine, iron-saturated transferrin, and bathocuproine disulfonate, a copper chelator. After a short period of growth, the 3 cell lines were successfully weaned from the feeder layers but continued to require human serum and the chemical supplements for up to 9 months of culture. The cell lines are currently grown in RPM1-1640 medium and fetal calf serum without further supplementation. The NU-DHL-1 cell line was established from the involved lymph node of a 73-year-old White male with diffuse large-cell lymphoma. The cell line expresses cytoplasmic IgM/lambda heavy and light chains, is Epstein-Barr virus (EBV)-negative, and is positive for several B-cell markers, indicating that it is derived from a mature-B-cell neoplasm. The NU-DUL-1 cell line was established from the cerebrospinal fluid of a 42-year-old White male with undifferentiated lymphoma, non-Burkitt's type, who initially presented with a mediastinal mass and had subsequent involvement of the central nervous system. The cell line is EBV-negative, but surprisingly it is positive for early B-cell markers. The NU-AmB-1 cell line was established from the abdominal mass of a 12-year-old Hispanic male with undifferentiated lymphoma, Burkitt's type. The cell line is EBV-positive and expresses early B-cell markers. All 3 cell lines are aneuploid or pseudodiploid and contain chromosome 14q+ abnormalities including a newly described complex translocation t(?;1;8;14) in the NU-AmB-1 cell line. The establishment of these cell lines was made possible by refinements in the cell culture of the human malignant lymphomas. The availability of well-characterized lymphoma cell lines with specific chromosomal translocations will aid molecular and cellular studies designed to identify the biological significance of genomic rearrangements.