Aims: To compare the disinfection ability of two widely used electrolytic generation systems (ClorTec and MIOX) and the conventional chlorine disinfectant (sodium hypochlorite) using three strains of Bacillus subtilis spores and MS2 bacteriophage. Methods and Results: Three B. subtilis aerobic spore strains (ATCC1A1, 35021 and 35946) and the bacteriophage MS2 (ATCC 15597-B1) were propagated and sporulated. Four indicator organisms were exposed to four disinfectant treatments for comparing the effectiveness of inactivation: hypochlorite, ClorTec, MIOX and MIOX-anode. The results indicated that the two electrolytic generation systems were as effective as the conventional chlorination for the inactivation of micro-organisms used. Some data points showed the variation using ANOVA analysis, in which the inactivation of MIOX and ClorTec was higher than that of hypochlorite. Conclusions: The ClorTec and MIOX systems are quite similar to hypochlorite in the inactivation-effectiveness for aerobic spores and bacteriophage in drinking water. Significance and Impact of the Study: Laboratory-scale investigation proved that gaseous chlorine could be replaced by either ClorTec or MIOX systems for the drinking water treatment utilities, which still could maintain the same disinfection efficiency.