OBJECTIVE: To determine the bacteriology and antibiotic sensitivity of the bacterial isolates in chronic maxillary sinusitis patients seen at the Kenyatta National Hospital. DESIGN: Cross-sectional study. SETTING: Kenyatta National Hospital, ENT department. SUBJECTS AND METHODS: Seventy-three patients had bilateral sntral washout done and the lavage submitted for culture and anti-microbial sensitivity between January and June 1996. RESULTS: Antral lavage yielded secretions in 63% of patients but bacteria were cultured in only 28.8% of the specimens. The isolates included Streptococcus pneumonia (22.2%), Staphylocococus albus (18.5%), Staphylocococus aureus (11.1%) and Enterobactericiae (11.1%). Anaerobic bacteria were cultured in 22.2% of the specimens. Of the commonly used antibiotics, there was high sensitivity to erythromycin, cefadroxyl, chloramphenicol and amoxicillin and poor sensitivity to ampicillin, cotrimoxazole and perfloxacin. CONCLUSION: The bacteriology of chronic maxillary sinusitis at Kenyatta National Hospital is generally similar to that found elsewhere. The bacteria are susceptible to relatively affordable antibiotics like amoxicillin, erythromycin and cefadroxyl.