Platelets play a special role in the systemic inflammatory response syndrome, as they acquire the ability to become activated and aggregate. Literature has no direct evidence of a link between platelet aggregation activity and the severity of the systemic inflammatory response syndrome in patients with pulmonary tuberculosis. The aim of the paper is to study platelet aggregation in patients with pulmonary tuberculosis with severe systemic inflammatory response syndrome. Materials and Methods. Spontaneous and induced by ADP (0.1, 1.0 and 5.0 ml) platelet aggregation was determined by Born turbodynamic method. The study enrolled 27 patients with severe and 33 patients with indolent systemic inflammatory response syndrome Spontaneous and induced by ADP (0.1 and 1.0 ml) platelet aggregation was evaluated in absorbance units (a.u.); platelet aggregation induced by 5.0 ml of ADP was measured in percentage terms. Statistica 10 was used to process the results. Discrepancy tests were used to determine the significance of differences of mean values; McNemar’s test and Fisher’s exact test were used to estimate event rate, p<0.05. Results. In Group 1 spontaneous and induced by ADP (0.1, 1.0 and 5 ml) platelet aggregation was 0.85–2.65 (1.210.1) a.u., 0.81–3.67 (3.030.38) a.u., 1.06–6.25 (6.50.51) a.u., 5–66 % (39.53.6); in Group 2 – 0.84–1.36 (1.10.04) a.u., 0.77–2.49 (2.10.26) a.u., 0.64–5.49 (2.200.08) a.u., 8–66 (35.74.14) %, respectively. Frequency of spontaneous and induced by ADP (0.1, 1.0 and 5 ml) platelet hypoaggregation in Groups 1 and 2 was 33.3 % and 27.3 %; 14.8 % and 24.2 %; 0 % and 39.4 %; 14.8 % and 24.2 %, respectively; frequency of hyperaggregation was 14.8 % and 0 %; 11.1 % and 9.1 %; 29.6 % and 0 %; 0 % and 0 %, respectively. Conclusion. Platelet aggregation activity in patients with pulmonary tuberculosis is determined by the severity of the systemic inflammatory response syndrome. A pronounced systemic inflammatory response syndrome is associated with increased spontaneous and induced by ADP (1.0 ml) platelet aggregation in 14.8 % and 29.6 % of cases, respectively.