This study examined whether female directors lack the necessary experience-based characteristics for board committee membership, or whether there is a systematic sex-based bias against them. We tested predictors of the odds of membership on certain board committees for male and female directors and found evidence of sex-based bias in Fortune 300 firms after controlling for directors' experience-based characteristics. Men were preferred for membership in compensation, executive, and finance committees, and women were preferred for membership in public affairs committees. Implications for the selection of committee members are developed.