Background: Thrombocytopenia is a condition in which platelet (PLT) count becomes less than normal range in some abnormal cases. The normal range of thrombocytopenia varies from 150.000 to 450.000 cell/cm3 . There are some cases that lead to pseudothrombocytopenia. The most common causes of Pseudothrombocytopenia involving; instrument errors, hemodilutiona, heparin-inducedthrombocytopenia, immunemediated destruction of platelets and using Ethylenediaminetetraacetic acid (EDTA) as an anticoagulant. Pseudothrombocytopenia is phenomenon that platelet count turnto below the lower limit (150.000 cell/cm3 ) in vitro. This phenomenon typically caused by using anticoagulant that named EDTA which leads to platelet aggregation. Generally, pseudothrombocytopenia has no sign and symptoms or clinical significance, but false low platelet count may leads to unnecessary extra diagnostic tests and treatment. The false result of low platelet count leads to treating by platelet transfusion; this could be harmful in patients with increased intravascular platelet activation. Recently, this phenomenon named as EDTA-dependent pseudothrombocytopenia. Four woman visited the laboratory for routine blood investigations, sever thrombocytopenia appeared. In this report, two of these cases will be discussed including how can differentiate between real thrombocytopenia and pseudothrombocytopenia. Objective: To avoid laboratory mistakes and how solve this problem in the laboratories and what must do to write a true report. Results: The results of complete blood count (CBC) showed very severe thrombocytopenia and during collecting information's from all of them, no sign and symptoms or family history was detected. After replacing EDTA with sodium citrate as an anticoagulant it finally proved that the patient has pseudo thrombocytopenia. Conclusion: It is very important to differentiate the real low platelet count with pseudothrombocytopenia. Thus, re-test of CBC with other anticoagulant (Sodium citrate) and blood smear also must be performed.