In this study, the effect of blended cements containing additives on the heat of hydration and the rate of heat liberation was investigated. The blended cements were prepared by using clinker, ground granulated blast-furnace slag (GGBFS) and ground basaltic pumice (GBP). Two groups of specimens were prepared by the grinding method of intergrinding and separate grinding. For each group of specimen, two Blaine values of 2800 +/- 30 cm(2)/g and 4800 +/- 30 cm(2)/g and four different ratios of additives, which were 0%, 10%, 20% and 30% of clinker by weight, were used. The effects of the grinding method, the fineness and the amount of additives on the heat of hydration were also investigated. It was found that the heat of hydration was affected by the grinding method. Also, interground coarser blended cement specimens resulted in extended time to reach the second peak compare to the separately ground finer ones. A significant reduction in the total heat of hydration was achieved in the interground coarser specimens with 30% additives. The minimum heat of hydration was obtained from the interground specimens with 30% additives and Blaine value of 2800 +/- 30 cm(2)/g. Due to lower heat of hydration this cement can be used for mass concrete construction.