The aim of the present study is to investigate the effect of virgin olive oil on some blood parameters in male Albino rats. Thirty male Sprague Dawley rats, (90-110 g), were used in the present study and were divided into three groups (10 in each), 1st group (control), received basal diet and supplemented with 1ml saline. 2nd and 3rd groups received basal diet, and supplemented daily with 1ml/100gm B.W and 2ml/100 gm B.W of virgin olive oil (VOO), respectively. Blood samples were collected weekly from all rats. Whole blood was obtained for determination of some haematological parameters, while sera were collected for the assay of T3 and T4 hormone.