The description of dense gases and liquids still remains a challenge in thermodynamics. Recently, our group developed a new equation of state that is described by an attractive exponential contribution and a repulsive component that both are a function of polarizability volume and macroscopic volume. In this Letter, we apply this equation of state to moderately dense gases of CO, N-2 and O-2 over a broad temperature range. Literature data is excellently reproduced with the new equation of state and in comparison to the Ideal Gas Law or the original van der Waals equation of state gives substantial improvement. (C) 2011 Elsevier B.V. All rights reserved.