To obtain a basic polycondensate useful particularly as a suitable post-treating agent for enhancing the wet fastness of color of a dyed or printed textile material in nearly a quantitative yield by a simple process.

There is provided a process for producing a basic polycondensate, comprising: (a) reacting an amine of the formula [wherein R1, R2, R3, and R4 are each independently hydrogen or an alkyl (which is unsubstituted or substituted with amino, hydroxyl, cyano, or a 1-4C alkoxyl); and A is an alkylene (which is unsubstituted or substituted with or interrupted with one or more hetero atoms)] with an ammonium salt in the presence of an anhydrous solvent, and (b) reacting the protonated product from (a) with cyanamide at an elevated temperature.