Solvent de-waxing process is a good way to decrease the pour point and enhance the physical and molecular properties of heavy crude oils, in this study methyl iso-butyl ketone (MIBK) was used as solvent to separate wax from Sudanese petroleum crude oil (Rawat) which has high pour point (54^oC) and mean molecular weight (628) and low refractive index (1.4745) due to its high saturates content; especially its n- paraffins content (47.14%) and consequently its high wax content (26.3%); and at the same time high aromatics content (42.50%). by using MIBK solvent at de-waxing temperature -10 ^oC and crystallization time 24hrs the yield of the separated de-waxed oil increases with increasing of dilution solvent ratio from 4/1 to 10/1. decreases the pour point of the de-waxed oil with increasing the solvent ratio from 4/1 to 10/1. it appears that when a high solvent to oil ratio (S/F = 10/1 by weight) is used and a higher yield of oil is achieved due to the increase of the solubility of the solvent.