Adenosine deaminase (ADA) activity increased in certain clinical conditions including tuberculosis and bacterial infections. In this study, the ADA isoenzymes patterns are assayed in ascites of different etiologies. Ninety two patients with ascites were selected and investigated to determine the cause of ascites. Total ADA and its isoenzymes are assayed spectophotometerically beside polyacrylamide gel electrophoretically. The total ADA in ascitic fluid secondary to parainfection in case of TB, abdominal cancer and liver cirrhosis is found to be 34.5±11.1, 87.6±23.6, 32.7±10.1 and 28.5±7.3 U L-1 respectivly. The ADA1m was 24.5±11.1, 4.3±1.9, 2.8±2.2 and 10.1±3.3 U L-1. ADA1c was 7.8±3, 16.5±6.2, 4.7±1.3 and 10.1± .3 U L-1 respectivly. ADA2 was 2.2±3.9, 65.9±33.5, 26.2±6.2 and 3.3±9.7 U L-1 respectively. Hence it is concluded that total ADA above 41 U L-1 and ADA2 above 32 U L-1 in ascetic fluid have high sensitivity value in TB peritonitis. The ascitic fluid ADA1m/ADA more than 50 % has high specificty value in parainfective peritonitis. Total ascitic ADA<41 U L-1 and ADA2/ADA ratio >50 % have high specificity in abdominal cancer.