Background: Antibiotics are frequently used to treat acne patients either as bactericidal or anti-inflammatory agents. However, with the increased use of antibiotics, resistant strains of Propionibacterium acnes began to emerge and have been associated with a poor treatment outcome. Objectives: Detection of staphylococcal and Propionibacterium acnes strains in cases of acne vulgaris in Assiut university hospitals, Egypt and antibiotic susceptibility patterns of Propionibacterium acnes isolates. Methodology: Microbiological samples were obtained from one hundred patients with inflammatory acne lesions. Samples were cultured on blood agar and mannitol salt agar media under aerobic conditions at 37°C for isolation of staphylococcal strains, and on blood agar under anaerobic conditions at 37°C for 3 to 7 days for isolation of Propionibacterium acnes. Bacteria were identified by colonial morphology, standard biochemical tests, and API 20A test for identification of Propionibacterium acnes isolates. Antibiotic sensitivity testing of Propionibacterium acnes strains was done against clindamycin, erythromycin, doxycyclin, trimethoprime/sulfamethxazole, tetracycline and levofloxacin. Results: Staphylocoocal strains were detected in 55% of acne cases, while Propionibacterium acnes were detected in 35% of cases. Most Propionibacterium acnes isolates were sensitive to levofloxacin (80%), followed by doxycycline (51.4%), tetracycline, trimethoprime/ sulfamethaxazole (20.0% for each) while showed highest resistance rates to clindamycin (85.7%) and erythromycin (82.9%). Conclusion: Levofloxacin was the most effective antibiotic for Propionibacterium acnes followed by doxycycline, while Erythromycin and clindamycin were the least effective antibiotics for Propionibacterium acnes.