Abstract: Derivatives of 2-amino-2-thiazoline exhibit muscarinomimetic properties in model experiments with isolated rat ileum. The activity of compounds strongly depends on the nature of substituents in 5-position of thiazoline ring. The most active spasmogenic compound is 5-iodomethyl-2-amino-2-thiazoline hydroiodide (ЕС50 =13±2 mМ). Its effect is very similar to activity of cholinergic agent pilocarpine (ЕС50 =14±4 mМ), but "intrinsic activity" parameter a (a=0.87±0.12) of 5-iodomethyl-2-amino-2-thiazoline was more significant. Ileum contractions induced by this compounds were inhibited by atropine. Derivatives of 2-amino-2-thiazoline (like pilocarpine) were not demonstrated nicotinomimetic properties. These compounds demonstrate very weak anti-AChE activity. For 5-iodomethyl-2-amino-2-thiazoline hydroiodide the IС50 value is 0.39±0.09 mM.