Manufacturing processes at steel and iron foundries generate a wide range of wastes. In order to establish a proper management policy for these wastes from an environmental point of view, an ecotoxicological and chemical characterisation of the wastes generated in two different Spanish factories was performed. Taking into account the manufacturing processes, the Spanish and European regulations and waste management trends, the parameter EC50 related to ecotoxicity and the metals Cr, Zn, Cd, Pb, Ni, Fe and Cu concentration were determined on TCLP and DIN 38414-S4 leachates respectively. Results showed a good qualitative agreement between the ecotoxicity of the samples and mobility of metals, with one exception, foundry sludges, where hazardous behaviour was related to the presence of phenolic species rather than the concentration of heavy metals.