Objective — to estimate the clinical and diagnostic value of soluble interleukin 2 receptor (sIL-2R) versus thymidine kinase 1 (TK1) and β2-microglobulin (β2-MG) in patients with lymphoproliferative diseases (LPD) of different clinical groups. Subjects and methods. The serum levels of sIL-2R, TK1, and β2-MG were measured using the kits of Bender Medsystems (Austria), BIOVICA (Sweden), and Сoulter Beckman (USA), respectively, in 81 patients with LPD (5 patients with Stage I; 23 with Stage II, 25 with Stage III, and 28 with Stage IV) before treatment. 57 and 24 patients were diagnosed with non-Hodgkin’s lymphoma (NHL) and lymphogranulomatosis (LGM), respectively. The recommended discriminatory levels (DL) of markers were 12.5 ng/ml for sIL-2R, 50.0 DU/l for TK-1, and 800.0—2400.0 µg/l for β2-MG. Results. It was shown that sIL-2R had a moderate diagnostic sensitivity in patients with LPD (53.2%). The highest diagnostic sensitivity (86.4%) was evidenced by TK1; and it was the least (40.0%) for β2-MG. The formed diagnostic sensitivity order for the markers TK-1>sIL-2R>β2-MG was characteristic for all the examined groups of patients with LPD. The mean level and proportion of excessive DLs of sIL-2R, along with those of TK1 and β2-MG, monotonically increased with tumor stage, confirming the association of these markers with the latter in LPD. There were no significant differences in the level and frequency of excessive DLs of three test markers between the LGM and NHL groups; and the NHL group showed no differences between T- and B-cell lymphomas and between indolent and aggressive lymphomas. In terms of the rate of excessive thresholds for LPD at the start of treatment, the pairs of β2-MG+TK1 and TK1+sIL-2R had a similar sensitivity equal to 87.7% (40.0% in stage I and 96.4% in IV). The excessive DL of at least one marker from a pair was considered to be positive. The similar data in the pairs were due to the high diagnostic sensitivity of TK1. Conclusion. When estimating sIL-2R, ТК1, and β2-MG before treatment, the diagnostic and therapeutic processes can be monitored in the majority of patients with LPD.