Introduction: Several studies have focused on the immunophenotype of the leukemic population at the time of relapse compared to that observed at diagnosis. Objectivew: The question of whether differences exist between surface antigens levels on blasts at the time of diagnosis and at relapse in cases of acute lymphoblastic leukemia (ALL) was addressed. Materials and Methods: A total of 25 All patients were included. Flow cytometry and fluorescein-isothiocynate conjugated antibodies were used to determined surface antigens levels. Results: The most frequently detected five antigens were I2 (n=21), CD10 (n=17), CD41 (n=16), CD2 (n=14) and CD7/CD19 (n=13/n=13) at the time of diagnosis and CD41 (n=21), I2 (n=20), CD10 (n=14), CD19 (n=16) and CD2 (n=12) at the time of relapse. There was a significant difference only between CD41 levels at the time of diagnosis and at the time of relapse (p=0.041). Conclusion: We found changes in antigen expressions at the time of relapse in ALL patients. This condition ought to be evaluated with reference to prognosis of leukemia.