The therapeutic effects of 2 dose levels of lincomycin and a reference drug (tylosin) were compared in 80 growing pigs with experimentally transmitted swine dysentery (SD). The pigs were allotted equally to 4 groups. Treatment was initiated 5 days after pigs were exposed to SD. Lincomycin was administered IM at doses of 11.0 or 4.4 mg/kg of body weight once daily for 3 to 7 days. Tylosin was injected IM at a dose of 8.8 mg/kg once daily for 3 days (highest recommended dose). The control (nontreated) infected pigs were not given the drug. The effects was terminated 22 days after exposure to SD. The effects were measured in terms of mortality, survival, physical activity, performance, and necroscopy findings. The 2 drugs reduced the clinical signs of SD. Pigs treated with either dose of lincomycin had a better treatment response than did pigs treated with tylosin, as evidenced by less mortality, longer survival time, and greater feed intake (P = 0.05). In addition, pigs treated with the larger dose of lincomycin, 11.0 mg/kg, had better treatment responses in 12 of the 14 measured criteria than did pigs treated with tylosin. Also, these pigs treated with the larger lincomycin dose had better treatment responses tha did the pigs treated wih the smaller dose of lincomycin, 4.4 mg/kg, as evidenced by dysentery, fecal consistency, physically active and intermediately active pig days, body weight gain, and feed intake.