Crossflow influence on steady Gortler vortices is studied in a pressure-driven boundary layer developing along a curved wall. Linear theory shows that crossflow is destabilizing in the long wavelength range. In the non-linear simulations, co-rotating vortices are transformed into counter-rotating vortices for accelerated boundary layers. The streamwise location, where counter-rotating vortices appear, depends on the amplitude of the pressure gradient. Linear studies indicate that a secondary instability may develop on the steady vortex profile. (C) 1997 American Institute of Physics.