Coagulase-negative staphylococci (CNS) represent an important group of etiologic agents of infections associated with plastic biomaterials, e.g. drains. In the present paper 33 strains of CNS were characterized. All of them were isolated from fluid of pleural drains in patients with lung cancer after pulmonary resection under conditions of antimicrobial prophylaxis. The most frequently isolated species were Staphylococcus epidermidis and S. warneri. The majority of CNS strains showed ability to produce slime and possessed hydrophobic properties of cell surface. Strains of CNS resistant to penicillin and oxacillin, but sensitive to amoxicillin/clavulanate were isolated most frequently. Only two methicillin-resistant strains, belonging to S. haemolyticus, were found. The obtained data indicate that CNS strains colonizing pleural drains had potential ability to adhere to smooth surfaces. Most of isolated strains were susceptible to antibiotics and chemotherapeutics routinely used in staphylococcal infections.