The Maternal Behavior Recorder (MBR) is a microcomputer program designed to record and analyze data from research on parental behavior of rats and other rodents. It is used to record the specific, characteristic patterns of maternal care in rodents: nest building, grooming, licking, crouching, and retrieval of pups. Moreover, it analyzes these events in terms of frequency and duration, allowing any events erroneously recorded to be corrected. The MBR can also simultaneously control observations made by one or two experimenters, and it calculates a set of reliability measures between them.