This paper proposes two tests of the hypothesis that not-for-profit hospitals (NFPs) behave differently than for-profit hospitals. The profit variability test states that the profits of an NFP will be less variable over time than profits of a for-profit hospital if the NFP maximizes utility subject to a profit constraint. The second test examines whether NFP profits respond less to change in exogenous factors, such as Medicare reimbursement rates, than profits of for-profit hospitals. Both tests, performed on panel data from 1983 to 1988, support the hypothesis that NFPs behave differently than for-profit hospitals.