<em>Background and aims.</em> <em>Streptococcus pneumoniae,</em> <em>Haemophilus influenzae</em> and <em>Moraxella</em> <em>catarrhalis</em> are the most common causative agents of acute respiratory tract infections (RTIs). The objective of this study was to assess their susceptibility to several antibiotics.<br /><em>Materials and methods</em>. A total of 58 strains (16 <em>S. pneumoniae</em>, 19 <em>H. influenzae</em> and 23 <em>M. catarrhalis</em>) were isolated from samples collected in two paediatric centres, and their susceptibility to commonly used antibiotics tested by E-test. <br /><em>Results</em>. Among <em>H. influenzae</em> isolates, 10.5% were resistant to ampicillin (all β-lactamase-positive), and 88.9% were susceptible to cefaclor. High β-lactam resistance rates (penicillin: 31.3% and cephalosporins: 18.7 to 31.3%) had been observed among <em>S</em>. <em>pneumonia</em> strains. Only 50% of isolates were susceptible to azithromycine. 91.3% of <em>M</em>. <em>catarrhalis</em> isolates β-lactamases producers were resistant to ampicillin while susceptible to the most tested antibiotics. <br /><em>Conclusions</em>. Except <em>M. catarrhalis</em> β-lactamases producing strains, frequency of antibiotic resistance was mainly observed among <em>S. pneumoniae,</em> and to a lesser extent among <em>H</em>. <em>influenzae</em> clinical isolates, suggesting the need for continuous surveillance of antimicrobial resistance patterns in the management of RTIs.