The efficient operation of producing wells requires reasonable estimates of well performance. This includes reservoir, wells and surface facility monitoring. Therefore, it is important to a petroleum engineer to have suitable methods to design artificial lift equipment, optimum production scheme and forecast production for planning objectives. The essential tool that required to monitor well performance is inflow performance relationship (IPR). This paper investigates the rate-pressure behavior for three phase flow in oil wells producing through the boundary dominated flow regime. A 300 data point were collected from simulation of six basic sets of fluid property data and relative permeability curves with five different values of water cut 20%, 40%, 60%, 80% and 90 %. Reservoir properties varies as follows: initial pressure ranging from 2100 to 4800 psi; temperature of 160 to 220?F; oil gravity of 25 to 50 ?API; gas gravity of 0.5 to 0.65; drainage radius of 526 to 1050 ft; height of 25 to 40 ft; porosity of 12% to 24%; permeability of 10 to 350 md; irreducible water saturation of 10% to 55%; critical gas saturation of 5% to 6% and residual oil saturation of 5% to 45%. From simulation outcomes analysis, empirical model of inflow performance relationship for three-phase flow was developed based on non-linear regression analysis. Statistical and graphical analyses were used to evaluate the performance of the developed model. The obtained outcomes include an average relative error (ARE) of 0.76 and coefficient of regression (R2) of 0.998. The proposed model of IPR was compared to other vertical inflow performance relationships available in the previous works. The presented correlation exhibited suitable approximations of well performance over a wide range of operating circumstances.