Abstract: This study was carried out to investigate serologically and molecularly the prevalent species of Salmonella present in four broiler chicken flocks in Kalubia governorate, Egypt. A bacteriological examination was done on a total of 1073 samples that collected from 293 chickens (127 apparently healthy, 62 diseased with whitish watery diarrhea and 104 dead broiler chickens). These samples included cloacal swabs, gall bladders, yolk sacs, spleens and livers. The colonial morphology, microscopical and biochemical identifications of isolates revealed presence of 51 strains of Salmonella representing; 10 (2.55%) from apparently healthy chickens, 18 (7.03%) from diseased broilers and 23 (4.69%) from dead birds. Positive Salmonella strains were present as percentages of 3.84, 4.15, 5.06 and 5.18% from flocks 1, 2, 3 and 4, respectively. Using slide agglutination test, serotyping of the isolated strains according to somatic (O) and flagellar (H) antigens detected presence of 19 S. enteritidis (37.25%); 10 S. infantis (19.60%); 1 S. chiredzi (1.96%); 4 S. kentucky (7.84%); 15 S. typhimurium (29.41%) and 2 S. tsevie (3.92%). There was a variation in the presence of Salmonella species serotypes in each of the examined flocks. Molecular characterization using Polymerase Chain Reaction (PCR) produced positive amplification of 284 bp fragments of invA genes (100%) specific for all members of Salmonella species. From the previous results, it could be concluded that there are different Salmonella serotypes including S. enteritidis, S. infantis, S. chiredzi, S. kentucky, S. typhimurium and S. tsevie circulating in broiler chicken farms in Kalubia governorate, Egypt and the most prevalent ones are S. enteritidis and S. typhimurium.