Cytogenetic studies on four patients with T-cell lymphomas are reported. In all four the short arm of chromosome No. 6 (6p) was abnormal. In three cases it was involved in a translocation, and in one there was a deletion of the terminal part: del(6)(p23-24). One of the translocations could be identified as a t(2:6)(q24;p24). Identification was not possible in the others. These 6p anomalies were associated with complex structural and numerical abnormalities of other chromosomes in three out of four cases. In three patients chemo- and/or radiotherapy administration preceded cytogenetic investigations.