This study analyses the Environmental Kuznets Curve Hypothesis (EKC) with direct material flow data from the USA, Germany, Japan, the Netherlands and Finland in the years 1975 to 1994. Recently, there has been a discussion concerning the relevance of the EKC hypothesis suggesting that also the intensity of material use should decline with income growth. The EKC hypothesis has not been widely tested with direct material flow data, and this paper presents one of the first attempts to do such tests. The results of the empirical hypothesis tests indicate that the EKC hypothesis does not hold in the case of aggregated direct material flows among industrialised countries like Germany, Japan, the USA, the Netherlands and Finland.