A preparation for performance of renal clearances in the conscious dog is described. The important aspect of the technique is the use of a Pavlov sling and a specially designed restraining apparatus. Of most importance is the use of a 7 French Swan-Ganz balloon-tipped catheter for urinary bladder catheterization. The use of male dogs obviated the need for an episiotomy. No special training of the animals was required. The animals tolerated long-term and repeated catheterization without any evidence of infection or trauma.