Studies of the kinetic sorption of nicotinic acid have demonstrated that the ionites AH-22, AH-31 and IR-45 absorb it quantitatively from water solutions. The static exchange capacity of nicotinic acid makes 3.5 mmole/g for AH-22 and IR-45 and 2.0 mmole/g for AH-31 and remains unchanged after ionite sterilization. Ionite AH-22 absorbs also quantitatively nicotinic acid from reaction mixtures used in its microbiological synthesis from 3-methyl pyridine. Formic acid (2n) desorbs entirely nicotinic acid from the above ionites. The sorption of nicotinic acid on AH-22 and IR-45 ionites is associated with diffusion processes; there is no chemical interaction between nicotinic acid and the ionites tested.