Stable isotope compositions of carbon and nitrogen (expressed as
δ13 C and δ15 N) from the European common cuttlefish ( Sepia officinalis) were measured in order to evaluate the utility of using these natural tracers throughout the Northeast Atlantic Ocean and Mediterranean Sea (NEAO-MS). Mantle tissue was obtained from S. officinaliscollected from 11 sampling locations spanning a wide geographical coverage in the NEAO-MS. Significant differences of both δ13 C and δ15 N values were found among S. officinalissamples relative to sampling location. δ13 C values did not show any discernable spatial trends; however, a distinct pattern of lower δ15 N values in the Mediterranean Sea relative to the NEAO existed. Mean δ15 N values of S. officinalisin the Mediterranean Sea averaged 2.5‰ lower than conspecifics collected in the NEAO and showed a decreasing eastward trend within the Mediterranean Sea with the lowest values in the most eastern sampling locations. Results suggest δ15 N may serve as a useful natural tracer for studies on the population structure of S. officinalisas well as other marine organisms throughout the NEAO-MS.