To follow  up the  response of  acute  lymphoblastic  leukemic

(ALL)   patients   to   chemotherapy   treatment   and  for   prognosis, diagnosis,  the total Sialic acid  (TSA) levels was studied as a tumor marker. The study included 40 patients (male = 22, female =18) with (ALL)   were   tested   for   the   serum   and   leukocytes   homogenate concentrations  of total sialic acid (TSA)  before and after  treatment with    six   different   chemotherapy   protocols.                      While   significantly increased ( P< 0.001  ) as compared to the heal thy individuals group, serum   and   leukocytes  homogenate   TSA   concentrations   dropped significantly   (   P<O.OOl )   after   treatment   with   each   of   the   six chemotherapy  treatment  protocols,  as  compared  to  ALL  untreated

patients. A linear correlation relationship ( r2  = 0.951 4 ; r2 = 0.9451)

was  found  between  TSA  concentrations  and  the  period  of chemotherapy  treatment    in  serum  and  leukocytes  homogenate.  A linear correlation relationship (r2  = 0.9965) could be found between percentage  of  serum  total  sialic  acid  and  percentage  of  leukocytes

homogenate total sialic acid. The results of this study strongly support the role of TSA as a marker for the disease and suggest that it could be used for progression and prognosis of ALL patients, in addition we strongly suggest that there was a positive relationship between TSA level in serum and leukocytes.