Its rising incidence, virulence factors and antibiotic resistance rate makes it difficult to treat Pseudomonas aeruginosa infections. The aim of this study was to compare virulence factors and antibiotic resistance of P. aeruginosa isolates from cystic fibrosis (CF) and other lower respiratory tract infections. Isolates from patients (n=125) were divided into two groups. The isolates in the first group were from CF patients (n=64). And in the other group isolates were from lower respiratory tract samples, from patients that did not have CF (n=61). The antibiotic susceptibility tests were done by using disc diffusion method. As phenotypic tests; DNase, protease, elastase, hemolysis, and motility test were performed. The mucoid form of P. aeruginosa was detected in 29.7% of CF patients’ isolates, whereas in the other group (non-CF) this rate was 9.8% (p=0.011). Motility in the CF patients’ isolates was lower (84.4%) then the other group (96.7%). The presence of DNase was significantly low in CF patients’ isolates when compared to the other group (p=0.009). When the antibiotic resistance was compared; ceftazidime, imipenem and meropenem and piperacillin resistance was found significantly low in CF patients compared to isolates from the other group (p≤0.05). Information about virulence factor patterns and antibiotic resistance of P. aeruginosa isolates from patients with cystic fibrosis and the patients without cystic fibrosis can prevent the unnecessary usage of antibiotics and lead the way to new approaches in treatment..