Findings are reported on use of long-acting atropine tannate in 50 unselected cases of ureteral colic. Patients with that diagnosis on admission were immediately given atropine tannate orally and received it every four hours thereafter. Thirty-nine of 40 patients with ureterolithiasis benefited from the atropine tannate. Thirty-five required no narcotics. Four required narcotics on one or two occasions. One of the 40 did not benefit from the drug. It is the authors' impression that the amount and frequency of narcotic required was markedly reduced by orally given atropine tannate. In 10 patients with no confirmation of ureterolithiasis there was no benefit. Initial investigation shows atropine tannate to be valuable in treating ureteral colic. There were side-effects but none so objectionable as to preclude its use.