The effect of the impact ionization dead space on avalanche multiplication and noise has been assessed for uniformp‐i‐navalanche photodiodes. This has required the development of a new numerical technique. The well‐established McIntyre theory of avalanche noise [IEEE Trans. Electron DevicesED‐13, 164 (1966)], which neglects the ionization dead‐space effect, has been shown to overestimate the excess noise factor. The implications of the dead‐space effect, for ionization coefficient determination and the interpretation of measured excess noise factors, are discussed.