Various blood changes have been found associated with the onset and progression of bovine tuberculosis. In this regard study was conducted to find out changes associated with the prevalence of bovine tuberculosis (BTB) in cattle (n=200) from 10 randomly selected farms with the size ranging from 10-200 in suburb of Islamabad, Pakistan. Blood samples were collected from tuberculin positive and negative animals through jugular vein puncture. The samples were transferred to the National Veterinary Laboratories (NVL), Ministry of Food Agriculture and Livestock, located at National Agriculture Research Center (NARC), Islamabad for laboratory analysis. Of the 200 cattle tested; 3 (1.5%) cows showed positive reaction to bovine purified protein derivative (PPDB), whereas 4 (2.0%) cows showed positive reaction to avian purified protein derivative (PPDA). There was a significant (P<0.05) rise in white blood cells (WBC) count in mammalian PPD positive cattle (16.0×103/μl ± 9.85) compared to values obtained in mammalian PPD negative (10.75×103/μl ± 3.81) cattle. Mean corpuscular volume (MCV) is significantly (p<0.05) higher in mammalian PPD positive cattle (52.93 fL ± 1.79) compared to mammalian PPD negative cattle (49.21 fL ± 5.92). Neutrophiles percentage was significantly (P<0.05) lower in mammalian PPD positive cattle (28.67 %± 3.79) when compared with mammalian PPD negative cattle (31.73 % ± 9.49). Mammalian PPD positive cattle (3.0 % ± 2.0) showed significantly (p<0.05) lower eosinophiles percentage compared to mammalian PPD negative cattle (5.03 % ± 2.44). A significant (p<0.05) increase in serum total proteins (10.15 g/dl ± 3.38) and globulins (6.26 g/dl ± 3.31) in cattle, having positive reaction to mammalian PPD, as compared with total protein (8.75 g/dl ± 1.97) and globulin (4.99 g/dl ± 2.01) level in mammalian PPD negative cattle. 1379612690.php