To investigate the possibility of predicting the crushability of rocks from impact strength index, twenty-four different rock types were tested in the laboratory. The crushability results were correlated with the results of impact strength test and regression analysis was performed. A strong inverse linear relation between the crushability index and the impact strength index was found. The effect of porosity and density on the correlation was also shown. In addition, multiple regression analysis including porosity and density was carried out. The significances of the derived models were statistically tested. It was concluded that the crushability of rocks can practically be estimated from the impact strength index using the simple regression model. (C) 2010 Elsevier Ltd. All rights reserved.