OBJECTIVE: The purpose of this article is to describe a new tracking technique for using sclerosing foam with radiologic guidance. Thirty-nine men with varicocele underwent transcatheter foam sclerotherapy. Sclerosing foam was produced by the Tessari technique using 5% sodium morrhuate solution, and foam sclerotherapy was performed by the new tracking technique, the filling-defects technique, under digital subtraction angiography (DSA) guidance using a step-by-step process consisting of spermatic phlebography, injection of sclerosing foam as a negative radiographic contrast material, and rinse of the catheter. CONCLUSION: The DSA-guided filling-defects technique is a feasible method for tracking the sclerosing foam and should be used in the treatment of other venous disorders when using sclerosing foam with radiologic guidance.