The objective of the present study was to correlate the blood grouping with the capacity of drinking water. Total of 172 subjects participated in the present study. The subjects were students of Bahauddin Zakariya University Multan, Pakistan. For determining the blood type a slide with 3 drops of antiserum A, B and D was taken. The 3 blood drops were mixed with drops of antiserum A, B, and D respectively on the slide. Blood clusters together with antisera D shows the +ve Rh factor. Our variable was capable of drinking water per day and our work was to correlate the variable with blood group. All the subjects were questioned about how many glasses of water they drink per day according to blood group. It was concluded from the present study that female who had blood group AB- have greatest mean value and had a maximum capacity of intake of water and in males who had blood group O+ have a maximum value of mean that showed that O+ male had the greatest capacity of drinking water.