Minimum size limits have become an increasingly popular management tool in recreational fisheries. This popularity stems from the potential of minimum size limits to accomplish the twin goals of limiting overfishing and improving fishing quality through increasing the average size of fish caught. The success of minimum size limits in achieving these objectives depends in a complicated way on both the behavior of anglers and the biological mechanisms that guide the growth of the fish population. This paper examines these relationships and also considers the welfare implications of size regulations.