Campylobacter coli CK 205, isolated from swine feces, was examined for changes in cell morphology, protein and lipooligosaccharide (LOS) patterns during starvation-survial experiments. Bottles filled with sterile filtered A. dest. were seeded with campylobacters and incubated at 4-degrees-C and 37-degrees-C. Transition to the nonculturable stage occurred within 48 hours (37-degrees-C) and 2 weeks (4-degrees-C), respectively. In contrast to the culturability the electrophoretic studies showed no changes in whole cell protein or LOS patterns. The electron microscopic pictures revealed spiral and coccoid forms, partly with a slightly enlarged periplasmatic space or budding of the membrane. Totally intact non culturable spiral or coccoid forms might be regarded as dormancy forms that cannot be detected by conventional microbiological methods in water examination.