Borogypsum is a by-product of a boric acid factory. Approximately ninety thousand tons per year are produced by two boric acid factories in Turkey. The borogypsum consists primarily of CaSO4.2H2O, secondarily of B2O3, and some other impurities. In this work, the use of borogypsum as an additive in cement production was studied. For this, the proportion of B2O3 in borogypsum was gradually decreased by water extraction. Refined borogypsum was mixed with Portland and trass cements and its effects on the setting and mechanical properties of these mixes were studied. It was concluded that refined borogypsum can be used for Portland and trass cements.