ABSTRACT: Background:- Alkaline phosphatase is the group of hydrolytic enzymes that are involved in the cellular metabolism. Alkaline phosphatase in saliva is used as an indicator of gingival inflammation, bone metabolism and other oral lesions like premalignancies and oral cancer. Aim and objective: To estimate the levels of Salivary Alkaline Phosphatase (S-ALP) in smokers and tobacco chewers associated with diabetes and diabetics without any habits. Materials and Methods: The study includes 30 cases and 10 control. 30 cases divided in group A, B and C and control group D: (1) Group A - 10 smokers who are diabetic. (2) Group B - 10 tobacco chewers who are diabetic. (3) Group C - 10 nonsmokers and non-tobacco chewers who are diabetic. (4) Group D - 10 nonsmokers, non-tobacco chewers and nondiabetic as control. Saliva was collected from the subjects of the above mentioned groups and the levels of S-ALP were estimated using a semi auto- analyzer and comparison was made. Results: The result reveals increase in the alkaline phosphatase levels in saliva of smokers and tobacco chewers with diabetes group (Group A, B). Non-smokers and non-tobacco chewers with diabetes group (Group C) had higher level compared to the control group (Group D). Conclusion: Salivary alkaline phosphatase is a clinical biomarker that is used to determine the oral diseases due to adverse habits and diabetes at its early stage.