An effective, non-surgical method of sterilization is needed for controlling growth of the dog population. Intraepididymal injection of 0.5 ml or 1.0 ml of an aqueous solution of 3.0% chlorhexidine digluconate in 50% dimethylsulfoxide (DMSO) given into each tail of the epididymides of dogs resulted in azoospermic ejaculates by days 35 or 42 after treatment. The azoospermia induced by treatment was long-lasting and likely irreversible. Intraepididymal injection of 1.0 ml of an aqueous solution of 4.5% chlorhexidine digluconate, without DMSO, given into each tail of the epididymides of dogs resulted in azoospermic ejaculates by day 28 after treatment, but the permanence of the azoospermia was not determined. The method of intraepididymal injection of sclerosing agents appears safe and suitable for large-scale sterilization programs for controlling dog populations.