Stable isotope ratio analysis has proven to be valuable for profiling illicit drugs, particularly for obtaining information regarding the drug’s synthetic origin. As part of its methylamphetamine profiling program (MPP) the National Measurement Institute of Australia has developed a capability to determine the stable isotope ratios of carbon, hydrogen and nitrogen of methylamphetamine. These ratios have proven valuable in determining the synthetic origin of methylamphetamine and information about its precursor. This capability has evolved over 10 years along with a quality system which allows for comparability of isotope ratio data obtained over time.