While many firms have set ambitious goals to increase diversity in their ranks, there is a dearth of empirical evidence on effective ways to reach them. We use a natural field experiment to test several hypotheses on effective means to attract minority candidates for top professional careers. By randomly varying the content in recruiting materials of a major financial services corporation with more than 10,000 employees, we find that signaling explicit interest in employee diversity more than doubles the interest in openings among racial minority candidates, as well as the likelihood that they apply and are selected. Impacts on gender diversity are less sharp and generally not significant.