Kahindi, R. K., Htoo, J. K. and Nyachoti, C. M. 2014. Short Communication: Effect of dietary lysine content and sanitation conditions on performance of weaned pigs fed antibiotic-free diets. Can. J. Anim. Sci. 94: 115–118. One hundred and ninety-two piglets (7.2±0.50 kg body weight) were fed corn–wheat–soybean meal based-diets to determine dietary Lys requirement in a 2×4 factorial setting [two sanitation conditions (SC): clean and unclean, and four dietary lysine contents: 0.94, 1.09, 1.25 and 1.43%]. The average daily gain (ADG) and gain to feed ratio (G:F) linearly increased (P<0.05) with dietary lysine contents, but were lower (P<0.0001) under unclean sanitation conditions from day 0 to 7 but not from day 8 to 21. Overall, dietary lysine contents did not affect average daily feed intake (ADFI), but unclean sanitation conditions reduced (P<0.01) ADFI; however, ADG was increased by both dietary lysine contents and SC? (P<0.001), whereas only dietary lysine contents affected G:F.