This study was carried out to assess the effect of the chlorine treatment into water for processing chicken products in each stage of slaughtering, with a special viewpoint related with reducing the viable number of microorganisms by which the water and the chicken body were contaminated. The mean bacterial number on chicken samples after picking process was log5.37$pm$0.20~5.84$pm$0.160CFU/$ extrm{cm}^2$. When assessed by standard plate count method, it was the higher one than any other processing stage in which eviscerating, pinning, packaging, and chilling was followed in order of the mean bacterial number. The coliform bacterial numbers on carcasses after sampling from different processing stages were log2.11$pm$0.63~2.88$pm$0.25MPN/$ extrm{cm}^2, which show almost similar numbers in each processing stage. But, after chilling process the number was decreased slightly. The bacterial counts in the water for scalding and chilling showed log3.43 $pm$ 0.59~5.06$pm$0.21 and log4.30$pm$0.21~6.62$pm$0.33CFU/$mell$, respectively. In the coliform counts for the water taken out from the 2nd chilling tank, the number was log1.97$pm$0.35~2.91$pm$0.22MPN/$mell$ which showed higher than those of the 1st and the 3rd chilling tank water. The effect of chlorination in reducing the bacterial numbers was accepted at the residual chlorine concentration of 1$mell$/$ell$by showing the reduction from $10^8$ to $10^4$CFU level and the numbers were decreased less than 10CFU at the concentration of 5mg/$ell$, when assessed by viable cell counts. In conclusion, these results suggested that chlorination In chilling water with final concentration of 5mg/$ell$was strongly recommended to reduce the bacterial numbers on final chicken products.