Nurse managers (NMs) and registered nurses (RNs) have key roles in developing the patient safety culture, as the nursing staff is the largest professional group in health-care services. We explored their views on the patient safety culture in four acute care hospitals in Finland. The data were collected from NMs (n = 109) and RNs (n = 723) by means of a Hospital Survey on Patient Safety Culture instrument and analyzed statistically. Both groups recognized patient safety problems and critically evaluated error-prevention mechanisms in the hospitals. RNs, in particular, estimated the situation more critically. There is a need to develop the patient safety culture of hospitals by discussing openly about them and learning from mistakes and by developing practices and mechanisms to prevent them. NMs have central roles in developing the safety culture at the system level in hospitals in order to ensure that nurses caring for patients do it safely.