This study focuses on detecting biofilm and planktonic bacterial cells of the genera Arcobacter and Campylobacter. This study is, to our knowledge, the first study deals with application of FISH procedure to detect biofilm formation on stainless steel coupons of Arcobacter-isolates from real-world environments. These bacteria can cause a lot of diseases. Especially, in the last decade, arcobacters have been increasingly isolated from feces of clinically healthy and ill animals, foods of animal origin and various types of water. Fluorescence in situ hybridization was used to detect biofilm and planktonic cells of selected microorganisms. This method was optimized and subsequently applied to biofilm samples prepared on stainless steel coupons. The study results indicate that fluorescence in situ hybridization is suitable for detecting biofilm and planktonic cells of the studied bacteria.