**Abstract:**
Critical pressure is one of the most important physical properties of the petroleum fractions, which commonly considered in compositional modeling studies and phase behavior calculations. This paper presents a comparison study among ten different correlations used to calculate the critical pressure of undefined petroleum fractions. A new correlation was developed for calculating the critical pressure of petroleum fractions as a function of the number of carbon atoms with an average error of 0.933977 % and correlation coefficient of 0.999585.

**Keywords:**
Critical pressure, petroleum fractions, Compositional Modeling Studies, Phase Behavior Calculations.