In the early 1970s, public health units were introduced to 32 Quebec hospitals. One of the reasons for introducing public health to hospitals was the beneficial influence this new structure, called "Département de santé communautaire" (DSC), was expected to have on the development of health promotion and prevention activities in the hospital. This study compared 19 DSC hospitals with 19 non-DSC hospitals that were matched for mission, size and location. The data came from a larger survey which had been conducted by the Canadian Hospital Association in Canadian hospitals in 1985. According to our results, DSC hospitals differed from their non-DSC counterparts mainly on dimensions related to their public health mandate (e.g. community programs, advocacy). They did not differ greatly on dimensions related to other health promotion and prevention activities within the hospital (e.g. inpatient and outpatient care, employees). These results suggest that while hospitals have not created organizational obstacles to the achievement of public health activities by DSCs, DSCs did not have the expected impact on hospitals.