Diammonium phosphate (DAP) is produced from industrial phosphoric acid that contains large amounts of anionic and cationic impurities (Co, Cu, Fe, Mn, Mo, Ni, Zn, F, As, Al, Hg, Pb and Cd). Consequently all those impurities will be found in DAP. However, the industrial DAP obtained can be used as fertilizers, but cannot be used for some industrial application like pharmaceutics and cosmetics. After purification, the price of DAP is three times more expensive than the same product before purification. The procedure for purification of industrial DAP is a recrystallization, by using several mixtures of solvents. The physicochemical characterization of this fertilizer upstream and downstream from the purification, through spectroscopic analyses and chemical analyses, shows that recrystallization eliminates impurities. Purified DAP was obtained, the physicochemical properties of which are comparable to those of the pure commercial DAP (Fisher).