The kinetics of chloride were studied in Sprague‐Dawley rats following the oral administration of Na36CI. The half‐life for36Cl−absorption from plasma was 19.2 h corresponding to a rate constant of 0.0361 h−1, while the half‐life for36Cl−elimination from plasma was 51.9 h, corresponding to a rate constant of 0.0134 h−1. At 120 h, radioactivity was highest in plasma, followed by kidney, lung, stomach, and spleen, and the lowest activity was observed in fat. Plasma and packed cells contained almost the same concentration of36Cl−. Plasma protein binding of chloride was significantly higher than liver protein binding. Subcellular distribution in liver fractions revealed that most of the36Cl−was located in the cytosolic fraction. The excretion of chloride occurred primarily by the kidney.