Moraxella (Branhamella) catarrhalis is now recognized as an important cause of respiratory tract infections. Over a two year period, Moraxella (Branhamella) catarrhalis was isolated in pure culture from 3.4% of the sputums collected from patients with symptoms of acute respiratory tract infections. It was the third most important pathogen isolated after Haemophilus influenzae and Streptococcus pneumoniae; 77% of the patients had an underlying chronic pulmonary condition. Prevalence, antibiotic sensitivity, and treatment options, will be discussed.