Heroin samples [76 South East Asian (SEA), 20 non-South East Asian (non-SEA) and 92 of uncertain origin] were analysed by inductively coupled plasma mass spectrometry for 73 elements. Hierarchical cluster analysis (HCA) grouped together the SEA and many of the non-SEA subgroups, and grouped together elements with similar chemical properties. K-means cluster, correlation and principal component analyses supported the HCA. Logistic models were created using continuous, discrete and a combination of continuous and discrete elemental data in order to predict the SEA or non-SEA origin of samples. The predictive values of the models were 68-100%, the most successful models simultaneously using both continuous and discrete concentration data.