The Mental Hygiene Legal Service (MHLS) provides legal services, advice and assistance to persons receiving care or alleged to be in need of care at inpatient and community-based facilities for individuals with mental disabilities and certain patients or residents of residential health care facilities. Created in 1964 and organized under Mental Hygiene Law article 47, MHLS represents such persons in judicial and administrative proceedings concerning admission, retention, transfer, treatment and guardianship. In addition to handling judicial proceedings, MHLS provides advice and representation regarding standards of care and other matters affecting the civil liberties of persons receiving care at facilities for individuals with mental disabilities.

MHLS can also be assigned as counsel or court evaluator in Mental Hygiene Law article 81 guardianship proceedings, and as counsel for respondents in proceedings commenced under the Sex Offender Management and Treatment Act (Mental Hygiene Law article 10).

MHLS for the Third Judicial Department has field offices in Albany, Binghamton, Elmira, Kingston, Ogdensburg, Oneonta, Plattsburgh and Tupper Lake.