A synergistic fungicidal composition comprising a fungicidally effective amount of at least one amino compound of the formula ##STR1## in which R represents optionally substituted, cycloalkyl or optionally substituted aryl,R.sup.1 represents hydrogen or alkyl,R.sup.2 represents alkyl,R.sup.3 represents alkyl andR.sup.4 represents alkyl, alkenyl or alkinyl, orR.sup.3 and R.sup.4, together with the nitrogen atom to which they are bonded, represent an optionally substituted saturated heterocyclic radical, which can contain further hetero-atoms,X represents oxygen or sulphur,Y represents oxygen, sulphur or the methylene group,m represents 0 or 1 andn represents 0 or 1,or an addition product thereof with an acid, metal salt or quaternizing agent, and at least one member selected from the group consisting of several individually known fungicides.