Zinc gluconate neutralized by Arg (Zeuterin; Ark Science Inc., Irvington, NY) is directly injected into the testes of dogs and has a 99.6% sterility rate; thus, a study was designed to test the effects of intratesticular injections of a Zn solution (Testrin (T); Ark Science Inc.) as a method of castration in swine. Within 10 litters, 7-d-old male pigs (birth weights of 1 kg, or greater) were assigned randomly to 1 of 3 intratesticular T dosages: 0.15 (n = 1/litter), 0.20 (n = 2/litter), or 0.30 mL/testicle (n = 2/litter). Scrotal area was thoroughly cleansed before T was administered by deep intratesticular injection using a sterile syringe and a sterile 28-gauge (1.26-cm long) needle. A surgically-castrated male (B) and an intact female (G) from each litter were designated as industry controls. Pigs were weaned at 21 d, mixed, and subsequently moved first to an off-site nursery then to a grower-finisher unit. Live weights were recorded at birth, weaning, and at the end of the study to calculate ADG, and scrotums were palpated monthly to monitor testicle growth. One month after injection, the proportion of pigs receiving 0.15, 0.20, and 0.30 mL/testicle with at least 1 testicle was 88.9, 95.0, and 70.0%, respectively, and declined to 55.6 (end of trial), 40.0 (end of trial), and 0% (4 mon after injection), respectively. Testrin-injected pigs were heavier (P < 0.05) at weaning than B, but neither pre-weaning (P = 0.549), post-weaning (P ≥ 0.185), nor overall ADG (P = 0.262) differed among treatments. Carcasses of T-pigs were heavier (P = 0.015) than B, but fat depths, LM area, and calculated fat-free lean yield were similar (P ≥ 0.333) among treatments. Although the LM from G and males treated with 0.20 mL T/testicle were darker (lesser L* value; P < 0.05) than the LM from B, LM color (P ≥ 0.071), drip and cooking losses (P ≥ 0.370), marbling (P = 0.164), firmness (P = 0.185), and shear force values (P = 0.378) did not differ among T-treated males, B, and G. Results indicated that male pigs can be effectively castrated by intratesticular injections of 0.30 mL T/testicle, and produce carcasses of equal composition and quality to B and G.