Introduction: Irrational antibiotic use is certainly complex and multifactorial problem, but also one of the major drivers for the emergence and spread of antimicrobial resistance. Methods: In prospective study throat and nasopharyngeal swabs from 450 school children, 6-15 years of age, from the city of Rijeka and the surrounding area, were processed. Two cross-sectional studies based on a structured questionnaire about knowledge, attitudes and practice regarding antibiotic use, that were given to 1000 parents of children attending elementary schools and 230 dental practitioners in outpatient settings of Primorsko-Goranska County, Croatia. Results: Antibiotic exposure in school children in the previous six months was associated with the carriage of antibiotic-resistant bacteria. The use of narrow spectrum penicillins was less common than the use of amoxicillin (26% school children, 33.1% dental practitioners) and amoxicillin with clavulanic acid (26% school children, 65% dental practitioners). Parents and dental practitioners had a high awareness of antimicrobial resistance. Conclusions: Antibiotic use is linked with higher resistance rates of respiratory tract pathogens. Parents' background did not influence the frequency of antibiotic use. Although there is a high level of antimicrobial resistance awareness among dental practitioners, there is still too much overuse of antibiotics, especially broad spectrum, and personal responsibility for rational antibiotic use should be increased.