The invention relates to process for the prepn. of 3,5-disubstituted-2,4,6-triiodoanilines of formula I [R1, R2 = CO2H and derivs., CONH2 and derivs.] by iodination of compd. II.  For example, 5-amino-N,N'-bis-[(2-hydroxy-1 -hydroxymethyl)ethyl]-2,4,6-triiodoisophthalamide (III) was prepd. by amidation of di-Me 5-nitroisophthalate with serinol to afford N, N'-bis-[(2-hydroxy-1-hydroxymethyl)ethyl]-5-nitroisophthalamide, which underwent redn. to afford II [R1, R2 = NHCH(CH2OH)2], which underwent iodination to give compd. III.