Many microorganisms previously unrecognized as food-borne or harmful are emerging as human pathogens transmitted by food and water. Arcobacter, the newly reclassified Campylobacter species, has been shown recently like an emerging pathogen (Phillips, 2001) of farm animals and human as well as possible routes of transmission via water and food. The objective of this work was to determine whether Arcobacter butzleri can survive chlorine water treatment and to study the survival strategies of this organism in chlorinated and non-chlorinated drinking water. Two survival experiments were conducted in flasks containing 100 ml water microcosms (chlorinated and non- chlorinated) filtered through a 0.2 um pore size and A. butzleri NCTC 12481 cells. The flasks were stored at 12C, in the dark. Samples were removed aseptically immediately after inoculation (To) and then periodically during the following 2 days (chlorinated drinking water) and 35 days (non-chlorinated drinking water) of inoculation. The experiments were performed by duplicate. The membrane integrity (Baclight viability kit), 16S rRNA (FISH technique and EUB 338 probe), DNA (PCR and 23S rRNA PCR- RFLPs) and culturability (TS agar plates without antibiotics) changes of A. butzleri cells were analyzed. The data showed that culturability of A. butzleri cells was lost at 5 min in chlorinated drinking water with 0.96 mg/l of free chlorine. At 24 h the cells showed membrane damage. After 24 h the amplicon specific for the 23S rRNA gene for A. butzleri (2500 bp) was detected, but the intensity of bands decreased at this time. The levels of 16S rRNA were constant during the chlorine treatment, so killing of bacteria with chlorine probably does not involve ribosome degradation. The organism was able to survive in non-chlorinated drinking water for at least 2 weeks and can remain viable for an extended period of time. A. butzleri was found to be sensitive to chlorine inactivation. Disinfection practices normally used in drinking water treatment would be adequate for controlling this organism, but continuous chlorination is essential when disinfection represents the only barrier to the spread of infectious agents via a contaminated water source, as recommended Rice et al. (1999). Includes 20 references, tables, figures.