The flow behind a rotor (or stator) blade row due to an arbitrary inlet distortion along both circumferential and spanwise directions is treated on the basis of classical actuator disc approximation. I t is shown that, in general, the spanwise and the circumferential distortion waves interact, so that the combined influence is not the sum of the influences of the two simple types of distortions. Numerical examples are then given to show the influence of the various conventional design parameters. Also illustrated is the role played by the cascade characteristics, represented by the variations of loss and exit flow angle due to changing inlet flow angles. I t is shown that both quantities exert a significant influence on the flow under inlet distortion. Using the same approach to the problem of incipient stall, the analysis shows that theoretically there can be two types of selfinduced distortion—a purely spanwise, axisymmetric type, and a traveling, circumferential plus spanwise type, the latter including a purely circumferential type as a special case. However, the analysis also indicates the interesting result that the purely circumferential type of traveling stall will, in all'likelihood, precede the other types. One aspect of dela}dng the incipient traveling (rotating) stall can then be reduced to two extremely simple rules with respect to the desirable design parameters and cascade geometry.