Small cylindrical pieces made of polyvinyl and steel were contaminated in the two concentrations of inoculum (10^7-10^8 CFU/ml and 10^3-10^5 CFU/ml) made from the clinical isolates and the standard strain of St. aureus Ps. aeruginosa. The pieces were disinfected for the period of 5,10,15,30,60,and 120min at room temperature in chlorhexidine solutions of 0.05,0.1,0.2,and 0.5%. Then bacterial growth was examined in recovery broth after 48h incubation at 37℃.From the pieces disinfected for 30min in 0.05%, 15min in 0.1% 10min in 0.2%, and 5min in 0.5% chlorhexidine solutions bacterial growth was not found excluding the pieces contaminated in high concentration inoculum made from the clinical isolates of Ps. aeruginosa, which showed marked resistance to chlorhexidine and the bacterial growth was negative after 120min in 0.05 and 0.1%, 60min in 0.2%, and 15min disinfection in 0.5% chlorhexidine. In comparison of polyvinyl and steel, both chlorhexidine concentration and disinfection time to inhibit bacterial growth was less with the pieces made of steel.