Bacterial biofilms are organised complex structures having polymicrobial nature in a single community, which provide protection to bacteria from antibiotics by various means. The aim of our study was to determine the prevalence of biofilm-forming bacteria in clinical isolates of acute and chronic rhinosinusitis (ARS and CRS) patients with sinonasal mucopurulence. To know the incidence of bacterial biofilms in patient with ARS and CRS, to study the microbiology of bacterial biofilms in ARS and CRS, to assess the role and effects of biofilm in ARS and CRS and to correlate the association between the formation of the biofilm and development of rhinosinusitis. This prospective study was carried out at a tertiary care centre in Eastern part of India, in which 60 patients were taken as sample size. All patients of rhinosinusitis between age-group of 10 to70 years, who came to our out-patient department, were taken for our study. Biofilm formation was observed in 50% cases and were absent in 50% cases of chronic rhinosinusitis in our study. 83.3% (50) of patients out of 60 patients got improved after treatment and recurrence was observed in only 16.6% (10) of patients. Recurrence was more at 3 months follow-up as compared to follow-up at 1 month, though it was not statistically significant. Though our study highlighted the incidence and role of biofilms in the development of chronic rhinosinusitis, but few more randomized controlled studies involving larger sample sizes should be done to exactly determine the pathophysiological role of biofilms in the development and recurrence of acute and chronic rhinosinusuitis.