Work has begun to upgrade the emergency department at the Queen's Medical Centre in Nottingham.
The hospital is spending £800,000 on improving services to ensure patients get quicker treatment.
The upgrade includes extra areas to check and treat patients and separate entrances for adults and children.
Managers said the current emergency department would stay open during the improvements, which are expected to be completed by February.
The work is geared towards improving services for patients with minor injuries and illnesses.
Building work got under way on Monday.
Trevor Hammond, matron for the emergency department at Nottingham University Hospitals NHS Trust, said disruption to patients and visitors would be kept to a minimum while work was in progress.