Introduction: Pseudomonas aeruginosa is an ubiquitous bacterium causes various community-acquired and nosocomial infections. In this investigation, we aimed to screen the antibiotic susceptibility patterns and the prevalence of virulence factor genes in a set of Pseudomonas aeruginosa isolated from nosocomial and community-acquired infections in the Northwestern of Morocco. Methodology: A total of 155 of Pseudomonas aeruginosa strains were collected (January 2015 - December 2016) from nosocomial and community-acquired infections at hospital centers and clinical laboratories in the Northwestern of Morocco. Antimicrobial susceptibility test was performed by the standard disk diffusion method. In addition, PCR assays were used for screening five virulence encoding genes (lasB, algD, plcH, exoA, and exoS). Results: Our results revealed that high level of antimicrobial resistance was detected towards aztreonam (27.1%) followed by meropenem (14.2%). The resistance to imipenem was significantly higher in strains isolated from nosocomial infections (12.7%) than strains isolated from community-acquired infections (1.5%). The results highlighted that lasB (98.7%) and exoS (98.7%) were the most frequent virulence genes. Conclusions: This survey provides data about phenotypic and genotypic properties of Pseudomonas aeruginosa emerged in the Northwestern of Morocco. It could be helpful for the health workers to improve infection control measures and to establish a surveillance system.