The influence of the gasotransmitter nitric oxide (NO) on the aggregation activity of platelets in vitro was analyzed using turbidimetric laser aggregometry, which records the light transmission signal of platelet-rich plasma. The aim of the study was to identify the dose-dependent and time-dependent effects of NO on the platelet aggregation process, as well as to establish the biochemical signaling cascades involved in these processes. Blood samples from 5 healthy donors were examined. It was shown that nitric oxide exerts a pronounced inhibitory effect on platelet aggregation, which is evident even at the minimum concentration 1 μM of the direct NO donor sodium nitroprusside. With an increase in concentration and incubation time, a statistically significant decrease in both the extent and the rate of platelet aggregation was observed. This indicates that the nitric oxide-mediated signaling pathway (NO/sGC/cGMP/PKG) exerts an inhibitory effect on platelet aggregation. The findings confirm the promise of using NO donors as agents for correcting platelet aggregation activity and demonstrate the high informativeness of laser aggregometry as a method for analyzing the microrheological properties of platelets. Keywords: platelet aggregation, gasotransmitters, sodium nitroprusside, nitric oxide, light transmission, turbidimetry.