Individual acetylation phenotype detected by metabolic phenotyping tests using a number of surrogate drugs, such as isoniazid is time consuming. The aim of this work was to determine the clinical prediction of acetylator phenotype in tuberculosis patients on medicare using blood group. 150 Tuberculosis patients (102 males and 48 females) on medicare were examined using  urinalysis technique for acetylator status and tile  method for blood group analysis. The result of the acetylator phenotypes revealed  that 46.7% were fast acetylators while 53.3% were slow acetylators. The highest frequency of fast acetylators were subjects with blood groups O+ve and A+ve. Similarly, the highest frequency of slow acetylators were observed in blood groups B+ve  and O+ve. Blood groups  AB-ve  and B-ve formed the lowest frequency of fast acetylators while A-ve and AB-ve formed the lowest percentage of slow acetylators respectively. Analysis of the blood groups and the acetylator phenotype  using Pearson’s correlation showed a significant (p < 0.01) relationship with a coefficient of 0.852; between the blood groups of M.Tb patients and the fast and slow acetylators (p < 0.05, with a coefficient of 0.76) respectively. We imply that for standard TB treatment, more treatment time be considered for subjects with blood groups that are predominantly fast acetylators (e.g., O+ve ) and close monitoring through the treatment period for predominantly slow acetylators (e.g B+ve). Further study on the serum concentration of each blood group for the drugs and molecular analysis of the blood phenotypes is advocated. reby recommended.