This work introduces a simple method for prediction of the flash point of different classes of unsaturated hydrocarbons including alkenes, alkynes and aromatics. Elemental composition is used as a core function that can be revised for some compounds by a correcting function. The predicted flash points for a data set of 173 unsaturated hydrocarbons are in good agreement with the measured values such that the root mean square (rms) error is 9 K. The estimated flash points for 76 furthers compounds have been compared with two new group additivity methods, where these methods can be applied, that the new method gives a lower rms value. It is shown that the new model can easily be used for any unsaturated hydrocarbons with complex molecular structures. (C) 2011 Elsevier B.V. All rights reserved.