With the sustained economic recession, suicide has been increasing in Japan (more than 300 000 victims annually since 1998), particularly among middle-aged employees. Development of preventive measures is needed; however, employees have limited knowledge of the basic information about depression and suicide. One office in Saitama Prefecture, Japan, has been provided with a mental health support program. An initial questionnaire survey was conducted in December 1999. It contained demographic data and information about working styles and daily habits, including alcohol and tobacco use, quality of sleep, social support, the general well-being schedule, and knowledge/attitude toward depression and suicide. Of 225 eligible people, 216 men and women participated. Most of them had stressful schedules and demanding jobs. Their subjective well-being was generally poorer relative to the reference. The mean score of knowledge was 10.5 (SD = 2.02) for 14 items. The accuracy rates ranged from 97.6% incorrect (false) for such items as 'Most suicide victims consult psychiatrists before their deaths' to 42.1% correct (true) for 'A suicidal individual tends to be accident-prone for traffic accidents and injuries.' One-fourth of them had unfavorable attitudes toward depressive colleagues. Neither age nor gender was related to knowledge level and attitude. Variations were observed in the knowledge that employees had toward depression and suicide. A program that provides employees with appropriate information related to mental health is needed.