The current study isolated and diagnosed pathogenic bacteria Salmonella from the domestic population of Musca domestica L collected from surrounding environments and overlapping with residential areas in Thi-Qar province. Thirty samples of Salmonella were isolated and diagnosed from 360 samples collected from markets, houses and hospitals of Thi-Qar provaince. The highest incidence of bacteria from external surface was during May and July (10.5%), while the lowest incidence was during January, February and November. This diagnosis was confirmed by a confirmatory test (API. 20) and the same diagnostic ratio given. All isolates were examined for their resistance to antibiotics which revealed that 46.6% of isolated Salmonella are resistant to nalidalic acid (86.7%), gentamicin (30%), amoxicillin (26.7%), norfloxacin and ampicillin (23.3 %). Diagnosed isolates were subjected to PCR, and this led to diagnosis of InvA gene in Salmonella.