Although factors related to suicide are complicated, mental health disorders are an important risk factor. It is anticipated that suicide prevention measures will be implemented from the perspective of improved psychiatric medicine. No national-scale study has been carried out in Japan on the state of psychiatric medicine and its influence on suicide since 2000. Moreover, many efforts not intended for suicide prevention have been shown to be effective for this purpose. Here, we conducted surveys to obtain basic data on suicide prevention and improvements in mental health care among 1,728 psychiatric hospitals and clinics in Japan in 2010. The incidence of suicide in psychiatric hospitals and clinics from January to December 2009 was estimated to be 100.5 for outpatients and 154.5 for inpatients per 100,000 patients. Regarding the duration from consultation to suicide, 87% of outpatients committed suicide less than one month following their last consultation. Moreover, approximately two-thirds of patients had undergone consultations for more than one year. A number of suicides in psychiatric hospitals and clinics occurred while patients were continuously undergoing treatment. Efforts shown to be effective in suicide prevention included risk assessment with multiple medical staff (i.e., doctors and nurses), a 24-hour crisis line, and a follow-up system for discontinued outpatients. We expect that the results of this survey will aid in the implementation of effective suicide prevention in psychiatric medicine.