Flow regimes spatial variability. This study investigates the spatial distribution of annual flow regimes within the Tur River basin, using 29-year records (1979-2007) of mean monthly flow, for 7 gauging stations. A multivariate, statistical classification of regime “shape” and “magnitude” is used to group annual regimes. The classification revealed two “shape” classes with different timing of major flow peaks and three “magnitude” classes. These results suggest regime “shape” is controlled by the seasonal distribution and nature of hydroclimatic inputs. As such, a framework can be provided around which to test hypotheses, making regional classification an important tool for hydrological research, particularly over large and complex geographical domains.