Abstract: An aqueous coating composition comprising a) an aqueous film-forming binder; and b) as corrosion inhibitor, a corrosion inhibiting amount of a product produced by reacting i) a mono- or di-aldehyde having the formula I:R--(CHO).sub.1 or 2 Iin which R is a C.sub.1 -C.sub.20 alkyl or alkylene group, optionally interrupted by one or more O- and/or N-atoms, or substituted by one or more hydroxy or cyano groups, or a C.sub.6 or C.sub.10 aryl or arylene group optionally substituted by one or more C.sub.1 -C.sub.10 alkyl groups, C.sub.1 -C.sub.10 alkoxy groups, hydroxy or nitro groups, or halogen atoms, with ii) a mono- or di-amine having the formula II:R.sub.1 --(NH.sub.2).sub.1 or 2 IIin which R.sub.1 is a C.sub.1 -C.sub.20 alkyl or alkylene group which is optionally interrupted by one or more O- and/or N-atoms, or substituted by one or more hydroxy or cyano groups, a C.sub.5 -C.sub.7 cycloalkyl or cycloalkylene group, a C.sub.6 or C.sub.10 aryl or arylene group or a C.sub.7 -C.sub.