The paper presents a new method for prediction of crystal densities of polynitro arenes and polynitro heteroarenes as two important classes of energetic compounds. The novel method assumes that densities of theses compounds with general formula CaHbNcOd can be easily obtained from their molecular structures. Two specific Structural parameters for polynitro arenes and polynitro heteroarenes, separately, in the new method can increase or decrease the predicted values. The predicted results show that this method gives reliable predictions of crystal densities as compared to well-developed group additivity methods for different polynitro arene and polynitro heteroarene explosives with complex molecular structures. (C) 2008 Elsevier B.V. All rights reserved.