Chronic maxillary sinusitis has been the subject of numerous investigations from the bacteriological point of view. Various techniques have been employed to obtain a representative specimen of the secretion or pus in maxillary sinusitis. Mixed infections and the presence of saprophytic bacteria have often been reported. During the period September 1965 to June 1966 we have examined 100 patients suffering from long standing chronic maxillary sinusitis. In the 100 patients experienced during this period 150 sinuses were examined. The nasal cavity was carefully sucked clean, a needle inserted into the maxillary antrum and sample taken from the first portion during irrigation. Hemophilus Influenzae was the most common finding (48.7%), next followed by Diplococcus Pneumoniae (29.3%). Staphylococcus aureus was found in 9.3% and the remaining strains were Staphylococcus albus and Streptococcus. During the winter season Hemophilus Influenzae was the domonating bacteria, while this particular bacteria decreased precentually during the summer season. Thick pus was usually found in Hemophilus Influenzae, while a mucous mixture usually indicated Streptococcus and other bacteria. In most cases only one strain was found. In 19 sinuses no growth of bacteria occurred. Hemophilus Influenzae dominated in the younger age groups (11-20 years), and there was a predominance of males in all age groups.