The goal of this study is to evaluate the efficacy of Diazo reagent as a diagnostic test of Salmonella infection in comparison to Widal test and blood culture in both cases and carriers of infection. 90 individuals with fever and abdominal pain, were grouped into three groups, 30 in each group. Group 1: 30 patients diagnosed as typhoid fever by Widal test, group 2: 30 healthy food handlers who were coming to the hospital for check up to obtain health certificate (carrier group), group 3: 30 individuals were healthy volunteers (control group). All of the three groups were undergone blood culture, Widal test and Diazo test. Diazo test had the highest diagnostic accuracy (97.7%) in comparison to Widal test and blood culture, while Widal test had 80% and blood culture had 70% accuracy in diagnosing typhoid. Diazo test was equal to Widal in diagnosis of carriers.