The hydrolysis of (trimethylamine)borane (TB) with the D+ form of ion-exchange resin suspended in organic solvent was studied. The hydrolysis retardation is observed in two cases : (i) due to inhibition by the hydrolysis side product, trimethylammonium, or (ii) due to resin pretreatment by long-chain cationic surfactants. The effect of hydrolysis inhibition is attributed to adsorption of surfactants on the resin which lowered the concentration of exchangeable deuterons in the reaction zone.