The epidemiology of suicide by motor vehicle exhaust was investigated. The impact of catalytic converters on suicides by this method was also studied. In 1994, this method of suicide was the third most common in Australia. Victims were predominantly middle-aged males. In 1986 stricter carbon monoxide emission standards & catalytic converters were introduced. However, an anticipated decline in the number of suicides from motor vehicle exhaust has not been observed. Recommendations are made.