Metabolism and elimination of d-tubocurarine-H3 were studied in 31 dogs. Combined renal and hepatic elimination accounted for over 85% of the injected dose within 24 hr. In the absence of renal function (ligation of renal pedicles), the liver greatly increased its capacity to transport d-tubocurarine into the bile. A search for metabolites of d-tubocurarine in urine and bile indicated that no metabolites were present in urine, but that approximately 1% of the injected tritium appeared in the bile in alternate molecular form.