Abstract: The present invention provides a fluid retention management system that records and displays fluid retention of a patient based on the weight of fluid entering and exiting the patient's body. Scales or other weighing devices are used to weigh the fluid entering and exiting the body so that the corresponding fluid volume may be calculated. The system automatically detects when a fluid container is being replaced. The fluid deficit of the patient is calculated according to the difference between the fluid volume entering the patient and the fluid volume exiting the patient. An operator is able to enter the specific gravity of the fluid and a fluid deficit alarm threshold. If the fluid deficit exceeds the alarm threshold, audible and visual alarms are generated.