The preparation of cyclohexanone-formaldehyde resins containing functional groups such as carboxylic acid, eater, phenol and vinyl is described. These resins were obtained by in situ modification of a cyclohexanone-formaldehyde resin. Modifier compounds were 1,4-cyclohexanedione, salicylic acid, o-cresol, p-cresol, citric acid, glyoxal, benzaldehyde, acetaldehyde, and acrylamide. Conductivities of the resin modified with glyoxal and acetaldehyde were 10(-4) and 3 . 10(-3) S cm(-1), respectively.