The Polymerase Chain Reaction (PCR) Laboratory of Menur Mental Hospital (RSJ) Surabaya is one of the facilities to detect the presence of the COVID-19 virus. The PCR laboratory has great potential as a place for infection through floor and wall media. The right type of disinfectant needs to be considered to prevent infection. This study aimed to analyze the disinfectant's effectiveness on the bacteria count on the floors and walls of the PCR Laboratory room at Menur Hospital. This study was conducted at the PCR Laboratory of RSJ Menur Surabaya using a crosssectional design. Sampling by the swab method was carried out before and after disinfection. Four rooms were determined as sample points, with three replications. All data were analyzed by paired T-test to determine the difference in the bacteria count before and after the disinfection process. The average bacteria count on the floor before disinfection was 8.3 CFU/cm2, and after disinfection was 3.5 CFU/cm2. Meanwhile, the average on the walls was 11 CFU/cm2 and 4 CFU/cm2. The statistical analysis showed a significant difference in the bacteria count before and after disinfection (p=0.04). The results showed that the disinfection process reduced the bacteria count on the floor and walls per applicable regulations, which was 0-5 CFU/cm2.