Abstract: Aminopyrimidine derivatives, their preparation, and agents containing them, and their use as fungicides comprising ##STR1## in which R.sup.1 is alkyl, alkoxyalkyl, alkylthioalkyl, cycloalkyl, alkenyl, alkynyl, cycloalkylalkyl, substituted aminoalkyl, phenyl, phenylalkyl, phenoxyalkyl, phenylmercaptoalkyl or phenoxyphenoxyalkyl, R.sup.2, R.sup.3 and R.sup.4 are H, alkyl, or phenyl, R.sup.5 is H, alkyl, cycloalkyl, cycloalkylalkyl, haloalkyl, alkoxy, alkylthio, alkoxyalkyl, R.sup.7 R.sup.8 N-,alkylthioalkyl, R.sup.7 R.sup.8 N-alkyl, halogen, alkenyl, alkynyl, phenyl, phenoxy, phenylalkyl, phenoxyalkyl, phenylmercaptoalkyl, phenylmercapto, phenylalkoxy or phenylalkylthio, R5 is H, alkyl, alkyloxy, alkenyloxy, alkynyloxy, alkylthio, halogen, or phenyl or R.sup.5 and R.sup.6 together form a chain, and R.sup.7 and R.sup.8 are H, alkyl, alkoxyalkyl, hydroxyalkyl, alkylthioalkyl, alkenyl, substituted formyl, phenyl or phenylalkyl, or R.sup.7 or R.sup.