Abstract: The net charges of the new potential myocardial imaging chelates M-BAT-TE and M-BAT-HM (M=Ga~(3+), In~(3+), Tl~(3+)) were determined by means of the ion exchange resin method.The net charges of these six chelates were all identified as + 1. In determining stability constants the pH eiectric potential method was used. The experimental results show that the magnitudes of the stability constants are in such an order: Tl-HM>In-HM>Ga-HM; TL-TE>In-TE>Ga-TE. This order is identical to the order of the heart uptake in mice of these chelates.