Enteric fever still remains a major endemic problem in India. Isolation of Genus Salmonella organisms from patient's samples is the gold standard, however it is well recognized that facilities for culture are not readily available or limited in many areas. Although the culture method is gold standard, it is however time consuming, expensive and the culture positive cases are also very less hence serological testing for Salmonella antibodies is also essential. In this book to study the reliability of a single Widal test and to find out the diagnostic significance of anti O & anti H agglutinin titer in the diagnosis of typhoid fever have checked with sources believed to be reliable in their efforts to provide information that is completely and generally in accord with the standard. In the absence of vaccination and any bacterial infection an elevated levels of anti O and/or anti H agglutinin titer of <1:80 is the diagnostic value for typhoid fever. Our study showed that baseline titers of Salmonella antibodies should be determined in different areas as it can show geographical variation.