Hides and Skins are protein based materials containing high amounts of water, which makes them a nutritionally rich media ideal for bacterial growth. Being also the essential raw materials in leather manufacture, it is vital to carefully protect them against bacterial action especially in the early wet processing stages. It is well known that bacterial action can seriously damage the fiber structure of hides and skins. Hair slip, red discoloration and grain pilling are typical examples of bacterial action can lead to damage with subsequent defects on the tanned leather. The present study identifies a new defect caused by bacteria known as "biofilm" on hides and skins. For investigation of the observed defective areas, two techniques were used: Scanning Electron Microscopy (S EM), and Real-Time Polymerase Chain Reaction (RT-PCR). The latter technique, RT-PCR, is a novel rapid method for unique detection, identification and quantification of microorganisms. The results, obtained by applying these techniques, verified the presence of "microbial biofilm" on the leather.