Abstract Oxoglutarate oxidation by purified potato mitochondria which had been stored at low temperature for 48 h or longer was stimulated by added coenzyme A. Exogenous coenzyme A was accumulated by potato mitochondria, both freshly prepared and aged, in a manner sensitive to uncouplers and low temperature. Coenzyme A was concentrated approximately 10-fold in the matrix under steady-state conditions. This coenzyme A uptake followed saturation kinetics with an apparent K m of 0.2 m m and a V of 4–6.5 nmol min −1 mg −1 protein, suggesting carrier-mediated transport. This transport was insensitive to an inhibitor of NAD + transport. It is suggested that plant mitochondria possess a specific carrier for the net accumulation of coenzyme A.