In this study we explore whether HMO-induced competition has contained expenditures in Minneapolis/St. Paul hospitals. Specifically, we assessed the impact of HMOs on revenue, cost, and net income per admission in Twin Cities hospitals from 1979 to 1981. Some HMOs have obtained negotiated discounts from hospitals. We found that hospitals which gave larger discounts did not have lower costs per admission. This finding suggest that discounts do not force hospitals to operate more efficiently. In addition, hospitals with a large share of patients from HMOs or government Medicare and Medicaid programs did not have lower costs per admission than other hospitals during the years from 1979 to 1981. This finding casts doubt on the claim that discounts are justified by lower costs for HMO or government patients. Finally, neither HMO market share nor discounts had an adverse effect on hospital profits. During the three years studied, hospital profits in the Twin Cities showed an upward trend. This study concludes that if competition is to succeed it must encompass more than HMOs. HMOs may be important, but they are only one agent in the market. Thus, public policy created to induce competition must go beyond the simple stimulus of HMO growth.