A case series study includes 35 patients, age between (3-14) years old, with acyanotic heart disease and secondary pulmonary hypertension, patients presented with sign and symptoms of infection at time of study and patients receiving antiplatelet drugs had been excluded from this study, in addition to those, if patient have anaemia or thrombocytopenia, should be excluded from platelet function test. Tests had been done for all patients are complete blood count, prothrombin time, activated partial thromboplastin time and platelet function test by PFA 200. This study reveals that there is a differences between the mean of the results for ACCH-PHT patients and the results of the normal control. 54%(19/35) patients had abnormalities in haemoglobin and erythrocytes (RBC) parameters, leucocytes (WBC) count normal in 97% (34/35) and platelet normal in 94% (33/35), the mean of the results was different from those of the normal control, In opposite platelet indices were abnormal in 97% (34/35)- mean platelet volume(MPV) was low in 65.7% (23/35) cases, plateletcrit (PCT) was low in 74.3% (26/35) cases. Platelet function was abnormal in 85% (29/34) cases. Prothrombin time was within normal range while activated partial thromboplastin time was prolonged in 11.5% (4/35) cases.