Electronic Journal of Differential Equations, Vol. 2013 (2013), No. 164, pp. 1-14. Title: Nonexistence of periodic orbits for predator-prey system with strong Allee effect in prey populations. Authors: Jinfeng Wang (Harbin Normal Univ., Heilongjiang, China) Junping Shi (College of William and Mary, Williamsburg, VA, USA) Junjie Wei (Harbin Normal Univ., Heilongjiang, China) Abstract: We use Dulac criterion to prove the nonexistence of periodic orbits for a class of general predator-prey system with strong Allee effect in the prey population growth. This completes the global bifurcation analysis of typical predator-prey systems with strong Allee effect for all possible parameters. Submitted March 25, 2013. Published July 19, 2013. Math Subject Classifications: 34C25, 34D23, 92D25. Key Words: Predator-prey system; nonexistence of periodic orbits; Dulac criterion; global bifurcation.