An approximate solution is found of a boundary‐value problem arising from the continuity equation in an inhomogeneous semiconductor, leading to rotational current vectors. Results are used to predict the effect of carrier‐concentration gradients on magnetoresistance. The predicted weak‐field effects are especially significant in degenerate semiconductors andn‐type III–V intermetallics where the ``intrinsic'' magnetoresistance is small. In strong fields, even small gradients in carrier concentration can completely alter the field dependence of the magnetoresistance. Experimental results indicate that transverse currents, which do not occur in the simple case discussed, do appear in general, and further perturb the magnetoresistance. The influence of inhomogeneous magnetic fields is discussed briefly.