It is known that nominally brittle materials may exhibit plastic deformation in indentation, scratching, and microcutting when the loaded region is sufficiently small. The present investigation is concerned with the erosive cutting of nominally brittle materials by the impact of a stream of solid particles and it is shown that ductile behavior should be observed when the particle size and velocity are within certain limits. Experiments on a number of nominally brittle materials confirm this prediction; the ductile behavior being inferred from both the rippled appearance of the eroded surface and the variation of volume removal with angle of impingement.