Inviscid transonic flow over the DSMA523a and Whitcomb airfoils and an airfoil described by a simple algebraic formula has been investigated numerically. The dependence of the flow structure and the lift coefficient on the freestream Mach number Moo and the angle of attack (X has been studied. The values of M_∞ and a at which steady-state flow becomes unstable have been revealed. The relationship between the flow nonuniqueness occurring in certain ranges of variation of M_∞ and α and the instability has been analyzed.