Knowing the bubble point pressure of the oil reservoirs is a key factor for the petroleum engineers in order to optimize the development of the oil field starting from the discovery phase till the abandonment. Thus any considerable error in estimating the bubble point pressure will lead to errors in the production and reservoirs engineering calculations. More than six hundred Egyptian oil samples of PVT analysis were used to improve the Wilson equation (K-Values) for estimating bubble point pressure. None of the published bubble point pressure correlations is particularly accurate when applied to Egyptian crude oils. Experimental work was conducted in PVT- Services Center of Egyptian Petroleum Research Institute (EPRI). In this work, the K-values correlation proposed by Wilson equation was modified by adding new terms such as API, GOR, and heptanes plus-fraction (C7+) of compositional analysis of the reservoir fluid. Multiple non-linear regression analysis is used to calculate the new equation constant after adding the new terms. The statistical error analysis shows that the Correlation coefficient , the average percent relative error , the standard deviation and the average absolute percent relative error of the modifying are 99.75 %, 1.77%, 8.08%, and 6.84 %, respectively. This correlation of K-factor can be applied not only to low and moderate pressure but also to higher pressures up to (4500 psi) by this modification. Evaluation among the bubble point pressure calculated from the modified Wilson equation and the literature published ones were done. Results confirm that the modified Wilson equation is more accurate one and it can be used for estimating the reservoir fluids characteristics in the absence of data measurement.