The purpose of this study was to evaluate the impact of the Mental Health Parity Act (MHPA) of 1996 on electroconvulsive (ECT) therapy in California. The study seeks to understand how this legislation, which increases annual and lifetime dollars for mental health services impacted a high cost behavioral health treatment (ECT) and how trends in the patient demographics changed from 1996 to 2000. The study investigates the patient demographics, diagnosis, length of stay, and payer category differences over a four year period. Additionally, literature was reviewed regarding the history of ECT use, characteristics of the patients, diagnosis, economic trends, utilization, payment type, state regulations, and the effectiveness of treatment. The literature also defines the Mental Health Parity Act (MHPA) of 1996 and how it may affect ECT treatment. This is a retrospective, descriptive study involving data aggregation and analysis from the California Office of Statewide Health Planning and Development (OSHPD) patient discharge data. Descriptive statistics were used in the analysis to identify any trends in patient demographics, diagnosis, length of stay, and payer type from 1996 to 2000. The descriptive statistics demonstrated that age, gender, race, and diagnosis were consistent for 1996 and 2000 with insignificant variations. Women were the primary recipients with a major diagnosis of depression. The average age of patients receiving ECT in both 1996 and 2000 was 57. There were minor variations among ethnicity and race between 1996 and 2000. Major diagnosis remained stable in that major depression was the most significant diagnosis followed by paranoid schizophrenia, bipolar disorder, and schizoaffective disorder for both 1996 and 2000. Length of stay for patients receiving ECT had a significant change from 1996 to 2000, decreasing by three days. This may be a result of a number of factors including the prompt initiation of ECT, the movement of inpatient ECT to outpatient ECT and its effectiveness in treatment. Other significant findings were the changes in payer categories from 1996 to 2000 for patients receiving ECT. The most significant changes were in the Medicare, Medi-Cal and private coverage categories. ECT utilization appears to be highest among government funded payment sources in both years. The third most prevalent category was ECT patients under managed care. Utilization went up 24.5% from 1996 and 2000. This significant increase may suggest that the MHPA of 1996 had significant impacts on mental health services, specifically the use of ECT. The analysis and results were discussed with the implications being that the MHPA of 1996 may have had significant effects on specific mental health treatments. The MHPA of 1996 gave parity to mental health benefits, increasing annual and lifetime limits for vi behavioral health services. This Act would potentially have a great impact on ECT since it is a relatively high cost treatment, which would allow patients in the private payer category to have access to an unusually expensive treatment. The results of this study may have meaningful implications for managed care companies and policy makers. The results provide additional support for ECT as an effective treatment to not only reduces length of stay and overall costs, but to provide an appropriate and valuable treatment to patients who may not have had access to it prior to the MHPA.