Background: Maxillary sinus puncture is considered the gold standard for diagnosing acute bacterial maxillary; sinusitis (ABMS) and for identifying bacterial pathogens in antimicrobial trials of ABMS. However sinus puncture and aspiration is an invasive., time-consuming procedure that is limited by discomfort to the patient and possible complications. Therefore, the diagnostic usefulness in clinical practice and patient enrollment in studies of ABMS is hindered and alternatives for maxillary sinus puncture ore being investigated. Methods: Vile designed a prospective clinical and microbiological outpatient study. Cultures obtained by endoscopically guided middle meatal aspiration were compared with those from sinus puncture and aspiration in 24 patients with ABMS. Results: Considering puncture and aspiration as the gold standard. endoscopy cultures provided a sensitivity of 80%, specificity of 100%, positive predictive value of 100%, negative predictive value of 78.6%, and correlation of 88.5%. Conclusion: In oar study, endoscopic sampling compared favorably with sinus puncture and aspiration.