The invention provides novel N-acylamino thiophene derivatives, e.g. N-(methoxyacetyl)-N-(5-bromo-4-methyl-2-methylthiothien-3-yl)alanine methyl ester, which are useful as fungicides. Other objects of the invention are fungicidal compositions comprising such novel compounds and methods of combatting phytopathogenic fungi with the acid of said novel compounds.