Suicide rate in Japan surged in 1998. Although the standardized mortality ratios (SMRs) of suicide in Osaka Prefecture, Japan had been mostly lower than the national SMRs of suicide between 1980 and 1997, they surpassed the increased national SMR of suicide in 1998 and 1999. We investigated whether the suicide rates for 1980-97 and the recent increased suicide rates in Osaka Prefecture were associated with socioeconomic factors. Time-series regression analyses of the suicide rate and socioeconomic factors were performed on respective data for five sub-areas in Osaka Prefecture. The suicide rates of young people and middle-aged men were more strongly associated with the job application and divorce rates for 1980-99 than for 1980-97. Some relations between the suicide rate and public assistance rate were found. The suicide rate was negatively associated with the marriage rate in some areas. The suicide rate of elderly women was strongly associated with the number of persons per household. The notable relation was found between the suicide rate of middle-aged men and the job application rate for 1980-99. The inverse relation between the suicide rate of elderly women and the number of persons per household was noteworthy.