The research centre of the Lachema nat Bohumín has developed new disinfectants with active chlorine on the basis of chlorinated derivatives of cyanuric acid. According to the physical and chemical properties, Dikon (sodium dichlorisocyanurate) was chosen as the best of these products; Later on, Dikon was given the trade mark Dikonit. Its minimum content of active chlorine is 55%. The purpose of the work was to test its bactericidal effect and to compare it with the effect of chloramin B. Tests on carriers and under practical conditions have demonstrated that, with the same content of active chlorine in solutions in practical use, Dikonit has almost the same bactericidal effect as Chloramin B produced so far. Due to this good bactericidal effect, Dikonit is a suitable means for prophylactic and focal disinfection in animal production and provides a good enrichment of the disinfectants based on active chlorine and produced in Czechoslovakia. It is recommended for prophylactic disinfection to use 1% solutions of Dikonit which are able to give the same effect in all parameters as warm solutions of 2-per-cent Chloramin B. The effective concentration to be used for focal disinfections can be deduced only approximately from the resistance of the infective agent with respect to the concentrations of Chloramin B, recommended as yet. An exact determination of the effective concentration would require experimental verification.