Evidence for the existence of acid phosphatase(EC 3.1.3.2) in the cell wall of higher plants has been reported repeatedly. The purification and some properties of the native cell wall acid phosphatase of tobacco cells were reported by our laboratory for the first time in 1990. On the other hand the studies on plant purple acid phosphatases have been made steady progress to discuss in the level of molecular biology. The cell wall acid phosphatase could be identified as a purple acid phosphatase.