Chronic administration of cholinomimetic (arecolin, pilocarpin, nicotin) and cholinolytic (bezohexonium, pedifen) drugs produces changes of different directions in the number of rosette-forming cells in the spleen of CBA mice immunized with sheep red blood cells. The analysis performed does not allow the effect of the drugs on immunologic processes to be accounted for by an immediate action on lymphoid cells or by an action of the function of the pituitary-adrenal system.