One hundred and thirty-six white managers in South Africa evaluated the varying performances of a series of thirty subordinates. Of the subordinates, two (one black, one white) had identically good performance descriptions, and two (one black, one white) had identically poor performance descriptions. Although the supervisors rated their overall performances as equally good or poor, they ascribed the success of the whites mainly to internal factors (effort, ability) and that of the blacks mainly to external factors (luck, easy job). Conversely, they ascribed the failure of the whites mainly to external factors and that of the blacks mainly to internal factors. The results suggest the operation of a ‘cognitive bias’ against blacks that may help to explain the persistence of racial discrimination in reward allocation in work organizations.