Configural face processes were tested using face recognition and face detection tasks in a comparison of acquired and developmental prosopagnosia. In the recognition task the two patients showed a very different pattern. The developmental patient does not show an inversion effect while the acquired prosopagnosia patient is better at matching inverted than normal stimuli. Moreover, there is no effect of face context on matching features in the developmental case while the acquired prosopagnosia patient shows a strong negative effect of context. However, in a speeded face detection task both patients are similarly unimpaired. The results are consistent with the existence of two separate face systems, one involved in face detection and the other in face recognition.