Objectives: Japan has the largest number of psychiatric beds per capita in the world. Both reducing the number of beds and preventing long-term hospitalization of individuals with mental illness is essential. This study surveys Japanese acute psychiatric units to investigate the process by which care management is provided. Care management is important to prevent those with a higher need for care from becoming long-term inpatients. Methods: All of the psychiatric emergency units (PEUs) and acute psychiatric treatment units (PAUs) in Japan (N = 234) were surveyed. Chief nurses of each unit completed items from a questionnaire that assessed basic characteristics of the unit and the implementation of each element of care management (i.e., triage, assessment, care conferences, and care plan development). Additionally, the association between care management and the clinical outcomes of the unit is examined. Results: The length of stay is 52.0 days for PEUs and 65.2 days for PAUs, and more than 25 percent of patients transferred to another unit or hospital, instead of being discharged. PEUs report slightly higher rates of offering each element of care management compared to PAUs. However, the overall rates are still inadequate, especially for the initial triage/screening and care plan development. The frequency of care conferences varies widely across units. While nurses and psychiatric social workers tend to participate fully, patient families and community service providers are not always included in case conferences. Care plans are developed in 58 percent of units. Only 20 percent of units had some kind of care management tool. Units implementing care management have more patients discharged to the community and have a trend for shorter lengths of stay, which suggests that care management is related to better clinical outcomes. Conclusion: The overall rates of care management in acute psychiatric units in Japan are inadequate. Dissemination of care management is, therefore, needed.