Mental health services experts suggest that managed care diminishes the need for arbitrary benefit limits and consumer cost-sharing. Data from 577 health plans were used to test the hypotheses that health maintenance organizations (HMOs) and carve-out plans are less likely to use benefit limits or service exclusions, have more generous limits, and have lower cost-sharing requirements than non-HMOs and non-carve-out plans. The results show that HMOs were more likely to use service exclusions and did not make less use of benefit limits. Carve-outs were less likely to use some coverage exclusions. Comparisons of the stringency of limits and cost-sharing provisions did not show consistent differences.