In this thesis properties of two crude oils and 7 mixed blends for lighter crude oil with lower sulfur content for „CPC blend“ and heavy crude oil with higher sulfur content for „E.B.C.O. of Iraqi Origin“ have been analyzed and tested. Blends were made in the reactor with a set time of 30 minutes at room temperature and pressure. Prepared samples of blends were determined by the following properties: density, viscosity, pour point, sulfur content, mass loss by thermogravimetric analysis and thermal flows by differential scanning calorimetry. Volatility of pure crude oils and blend 50 wt. % CPC blend/ 50 wt. % E.B.C.O of Iraqi Origin was determined for a period of 60 days. By determining of density and viscosity, it has been found that blends with higher proportion of heavier crude oil have higher density and viscosity. Viscosities of blended samples were analysed on top and the bottom to determine the homogeneity and stability through the period of 60 days. Pour point for lighter crude oil was -19 °C, -27 °C for heavier crude oil, while the blends pour point for sample 50 wt. % CPC blend/ 50 wt. % E.B.C.O of Iraqi Origin was determined at -22 °C. Sulfur content has a linear trend and is growing with an increase of the heavier crude oil that contains 2.46 wt. % of sulfur. Thermogravimetric analysis determined mass loss up to a temperature of 600 °C, with lighter crude oil CPC blend expected to have a higher loss of mass and volatility at low temperatures.