Comparative studies on the disinfectant activities of electrolyzed acidic aqueous solutions (EAAS; pH 2.5-2.6) and 0.2% benzalkonium chloride (Welpas) were carried out by the glove juice method. After triplicate determination of baseline levels of the hand skin flora in 128 volunteers, the skin was washed with flowing EAAS I or II for 90 seconds or a single application of 3 ml of Welpas. Bacteria on the washed hands were collected by the glove juice method, and the number of bacterial colonies formed in agar plates were counted. The activities of EAAS I and EAAS II were compaired with that of Welpas. The bacterial reduction rates of EAAS I and Welpas were 65.1% and 58.7%, and those of EAAS II and Welpas were 70.2% and 57.6%, respectively. The logarithmic reduction values of EAAS I and Welpas were 0.60 and 0.74, and those of EAAS II and Welpas were 0.57 and 0.52, respectively. There were no statistically significant difference among the three solutions under the present experimental conditions. Thus EAAS I and II may be useful disinfectants for the hands, however it is essential to examine the influence of frequent washing for clinical use. In addition, it is needed to establish water supply and drain systems to use this equipment.