Eosinophil cationic protein (ECP) was recently used for assessment of Schistosoma haematobium morbidity. In this study, the level of (ECP) in sera of schistosomiasis patients was significantly higher than control group, and this significance was higher in S. haematobium than S. mansoni groups. No association between level of (ECP) in serum and egg count in S. mansoni and S. haematobium patients was found. Comparing the correlation of ECP level in serum with Schistosoma antigen in both serum and urine, in S. mansoni there was a positive association between (ECP) in serum and serum schistosomal antigen but not with schistosomal antigen level in urine among S. mansoni infected patients. On the other hand, in-patients with S. haematobium infection there is strong association between (ECP) level in serum and the level of antigen in urine, but not with schistosomal serum antigen level. These results suggest that serum (ECP) may be useful and more sensitive and accurate marker of morbidity in S. haematobium infection than indirect measures.