Hospitals run by the Lancashire Teaching Hospitals Foundation Trust have been rated "Requires Improvement" in a report by the Care Quality Commission.
Royal Preston Hospital and Chorley and South Ribble Hospitals have now been told that they must improve their services for patients.
The report, which was published today, outlined issues surrounding the flow of patients through A&E and staff shortages in the Critical Care Wards at Royal Preston Hospital.
It also highlighted issues in the hospital's medical care, urgent and emergency services, surgery, intensive/critical care, Maternity and gynaecology, Services for children & young people and outpatients departments.
However, caring at the hospital was described as "good".
The A&E and urgent care department at Chorley and South Ribble Hospital has been downgraded from "good" to "requires improvement."
The report said: "The culture [in the department] was affected negatively by staff feeling unsure about plans for the future. They described an atmosphere of mistrust and suspicion. We also heard numerous staff tell us communication was not good which contributed to this.
"Staff engagement and communication was described as ‘awful’ by staff, particularly about the change from Emergency Department to Urgent Care Centre provision."
The department was however, praised for its open, no-blame culture of reporting and learning from incidents.
The inspections were carried out in September 2016.