The effect of infusions of citrated plasma given at varying rates on the plasma citrate level of infants has been studied. The plasma citrate as a rule rose from 0.17 to 2.0 mM/1. after single infusions to fall rapidly at first and more slowly later. In two instances levels of 2.6 and 2.8 mM/1. were observed. Considerable decreases in the calcium ion concentration, assuming unchanged total calcium values, were calculated. ECGs indicated some lengthening of the duration of the Q-T interval, compatible with a decrease in the calcium ion concentration, but to a degree less than expected. One infant suffered a nearly fatal reaction, considered to be tetanic in nature. The examination of the citrate in the plasma of an infant dead after infusion of plasma showed a high citrate level of 2.8 mM/1. It is assumed that normally physiologic forces are operative to counteract the calcium-ion-lowering effect of citrate.