
Introduction: Biofilms formation plays an important role in bacterial and fungal pathogenesis. Biofilms have been considered a virulence factor contributing to bacterial infections. Therefore, a reliable method for their diagnosis is necessary. Materials and Methods: In this study, biofilm formation of 86 isolates of bacteria and yeasts were detected by Test tube method, polystyrene petri dish method and glass slide method and the results were compared. Results: Slide method and Petri dish method were found better than the test tube method for studying biofilm formation with better sensitivity but poorer specificity. Conclusion: Slide method and Petri dish method can be safely used to find out pattern of biofilm formation by bacterial isolates and yeasts.