Background: For a long period, Salmonella infections are responsible for gastroenteritis outbreaks in developed nations and typhoid fever and nontyphoidal Salmonella bacteremia in developing nations. Typhoid is caused by Salmonella infection and has been detected in the Hospital and Health Center in Sammara city. The aim of current study was to investigate the correlation between some of immunological biomarkers (C3, C4) and hematological changes in patients infected with Salmonella bacteria in Sammara city, Iraq. Method: Samples obtained from participants were cultured on Nutrient agar plate. Identification of Salmonella infection was performed by using the VITEK 2 automatic system. Also, different cultural, bio-chemical, serological and molecular studies were used to characterize Salmonella organisms. Results and Conclusions: Data showed that out of 50 samples included, 25 were positive for Salmonella infection, while 25 samples were negative for Salmonella infection (The control group included 25 clinically healthy children without Salmonella infection matched for age and sex with pateints). The results obtained in present study showed that there was no significant difference in the level of PCV, RBCs and Hb with significantly higher (P<0.05) in typhoid patient compared to the apparently healthy control individuals. Also, that there was no significant decrease in WBC (P<0.05) when compared with the apparently healthy control individuals. The moderate increase in lymphocytes in apparently healthy individuals could be linked to environmental factors and also there was no significant effect on basophiles count. [ABSTRACT FROM AUTHOR]