Introduction: The Irish Mental Health Act (MHA) 2001 brings Irish health legislation into line with the European Convention for the protection of Human Rights.It replaced the older 1945 Act.The purpose of this study was to assess the impact of the MHA 2001 on involuntary admissions to a private psychiatric hospital before and after its implementation. Methods: All involuntary patients admitted to the hospital over a 3 year period for 2 years before and 1 year after the act was introduced were included.A retrospective case note review was undertaken.Data collected included number of days as an involuntary patient and discharge diagnosis.Data was analysed using SPSSv14. Results: A total of 204 patients files were examined. 94 and 70 patients were admitted in the 2 years before the introduction of the MHA, this fell to 40 admissions in the year after the MHA.The mean number of days that patients were involuntarily admitted for 2 years before the Act was 68.6, this fell to 24.9 days in the year after the act, p value < .001.The percentage of involuntary patients with a diagnosis of dementia fell and the percentage of admissions with schizophrenia and BPAD increased. Conclusion: There was a considerable reduction in the number of involuntary admissions and average length of stay after the introduction of the 2001 MHA.More bed numbers may be needed for acute adult admissions and less for long stay admissions.Patients human rights have been improved by the new act which is a positive consequence.