Purpose: This study aimed to determine the functional effects and mechanisms of the action of rosuvastatin on vascular and tracheal smooth muscle tissues. 
 Materials and Methods: Vascular and tracheal rings (2-3 mm) isolated from the thoracic aortas, pulmonary arteries, and tracheas of Wistar Albino male rats (250-300 g) were placed in chambers in the isolated tissue bath system. As the resting tension, 1 g was selected. Vascular rings contracted with 10-6 M phenylephrine after a 90-minute equilibration period. Tracheal rings contracted with 10-5 M acetylcholine. After the contraction was steady, rosuvastatin (10-8-10-4 M) was cumulatively applied to the vascular and tracheal rings. The defined experimental methodology was repeated following the incubation of selective inhibitors of signaling pathways and K+ channel blockers to ascertain rosuvastatin's functional effect mechanisms. 
 Results: In the precontracted rat vascular and tracheal rings, rosuvastatin induced concentration-dependent relaxation. The maximal relaxation level in vessel samples was 96%. On the other hand, the maximal relaxation level in tracheal samples was found to be 75%. The vasorelaxant effects of rosuvastatin were dramatically attenuated by endothelium removal, L-NAME treatment, and indomethacin incubation (up to 27%). With the incubation of tetraethylammonium, glyburide, 4-Aminopyridine, and anandamide, rosuvastatin-mediated vascular smooth muscle relaxation levels were significantly decreased (up to 38%). Moreover, With the incubation of tetraethylammonium, glyburide, and 4-Aminopyridine rosuvastatin-mediated tracheal smooth muscle relaxation levels were significantly decreased (up to 30%). 
 Conclusion: Rosuvastatin has a noticeable relaxing effect on the vascular and tracheal smooth muscles. The vasorelaxant effect of rosuvastatin involves intact endothelium, nitric oxide, prostanoids, and K+ channels (BKCa, KV, and KATP channels). Furthermore, nitric oxide, prostanoids, BKCa channels, KV channels, and KATP channels play a role in rosuvastatin-induced tracheal smooth muscle relaxation