The purifn. and crystn. of iopamidol (I) is achieved by adding 1-propanol or 2-propanol to an aq. soln. of I followed, if necessary, by azeotropic distn. to reduce the quantity of water in relation to the quantity of propanol, and thereby ensure a high I yield. The aq. soln. can be prepd. either by the dissoln. of crude I in water or directly from the reaction in which the I is formed. This process presents advantages to the routine prodn. of I since the crystn. is straightforward to perform, can be easily controlled, and is reproducible at an industrial scale.