Effect of taurine o binding of 45Ca2+ and 8-aniline-I-naphthaline culfonate by microsomes of rat brain cells was studied. Increased accumulation of Ca2+ in phospholipids of microsomes as well as a distinct decrease in the number of sites for binding of 8-aniline-I-naphthaline sulfonate were observed in presence of taurine. Activity of Ca2+-ATPase was simultaneously increased. The data obtained suggest that the effect of taurine on biomembranes is related to local alterations in their surface charge.