A field experiment was designed to examine the role of gender trait assumptions in occupational treatment discrimination. Professional personnel consultants evaluated male or female employees who were physically attractive or unattractive and masculine, feminine, or androgynous. Consultants made decisions about promotion, opportunity for special training, delegation of work assignments, and a child care leave of absence request in masculine, feminine, and sex-neutral occupations. Decisions about career development were strongly influenced by gender trait information, rather than by gender or attractiveness. In contrast, females were more likely than males to be granted a child care leave without pay, regardless of sex role. The results supported the assumption that the congruence between gender traits and the occupational requirements mediates occupational sex discrimination. Only for decisions involving competing role demands stemming from faily circumstances was there evidence that beliefs about appropriate roles for the sexes mediate discrimination. Implications of these findings are discussed in terms of new approaches for reducing sex discrimination in the treatment of employees.