Objective: To assess the use of bacterial culture findings for middle meatal samples obtained via anterior rhinoscopy, in the diagnosis of adults with acute rhinosinusitis.Materials and methods: Microbial cultures were prepared for 30 adult patients with acute rhinosinusitis and suspected bacterial involvement, using samples from the nasopharynx, and from the nasal middle meatus obtained via anterior rhinoscopy. Findings for the ipsilateral maxillary antrum were used as a reference.Results: Seventeen patients had a bacterial infection as verified by a positive culture from the maxillary antrum. Middle meatal samples had a similar sensitivity but a better specificity, positive predictive value and negative predictive value, compared with nasopharyngeal samples, although predictive values were not statistically significant at a 95 per cent confidence level.Conclusion: Anterior rhinoscopy with culture of middle meatal samples can be recommended as a diagnostic procedure for acute rhinosinusitis. The results can also guide the decision on antibiotic treatment.