Introduction:Landsteiner dividedblood into four groups A, B, AB and O depending on the antigens present on red cell membrane. The blood group substances A and B are not confined to red cells but can be detected in other tissue cells and in body fluids. They have wide distribution and have been found in serum and saliva. Those individuals whose saliva contains appropriate group specific substances (A, B and H) are called “secretors” and those whose saliva have only trace amounts or lacks such substances are called “non–secretors”.Bacterial colonization of the oral cavity with specific microbes is an important aspect for the formation of dental plaque and initiation and progression of periodontal disease.Blood–group antigens may play a role as their presence in saliva may cause bacterial aggregation which promotes bacterial clearance of the oral cavity. Materials and method:63 healthy subjects and 126 periodontal disease patients, including 63 gingivitis and 63 periodontitis, ie total of 189 subjects were tested for ABO blood groups and secretor status. Controls and patients were in age group of 20 to 70 years, with at least 20 teeth. ABO blood group was determined by slide agglutination method. Secretor and non–secretor status were determined byhemagglutination inhibition technique. Results:No significant difference was observed in the secretors and non–secretors for all the subjects of the three groups. Blood groupA shows maximum plaque score but minimal periodontal destruction. Blood group O shows minimal plaque score but maximum periodontal destruction. Significant difference was observed in total number of secretors and non–secretors of controls and periodontal disease.The secretor subjects were more prone for periodontal disease. Among the different blood group substance being secreted, the BH secretor status was the most common.Conclusion:No significant relationship of any particular blood group substance could be established to periodontal disease. A study with a larger sample could conclusively establish the possible relationship between ABO blood groups, salivary secretor status and periodontal disease.