Big Quill Lake, Saskatchewan, is an important breeding area for Piping Plovers (Charadrius melodus); the area hosts up to 8% of the continental breeding population, yet little is known about how the site contributes to the overall survival of this species. We studied the reproductive success of Piping Plovers at Big Quill Lake from 1993 to 1995. We located 208 nests and captured and banded 456 young. Nest initiation occurred from mid-May to mid-July, and median nest-initiation dates were 14, 13, and 13 May in 1993, 1994, and 1995, respectively. Mean clutch size for presumed first nests was 3.92 eggs. Nesting success was consistently high from 1993 to 1995, with Mayfield estimates of nest success ranging from 75 to 88%; nests initiated later in the season were less successful than earlier nests. The wide beach (200–1,000 m) at Big Quill Lake may have contributed to high nesting success by reducing efficiency of predators. Use of Big Quill Lake beaches by humans and cattle was also minimal. Fledging success varied dramatically, with 0.02, 1.35, and 1.78 young fledged per breeding pair in 1993, 1994, and 1995, respectively. Low productivity of Piping Plovers in 1993 was a result of low chick survival during a week of rain, cold temperatures, and high winds, rather than low nesting success. Fledging success in 1994 and 1995 was higher than the 1.24 chicks per pair required for population stability on alkaline lakes in the Northern Great Plains. This high productivity suggests that Big Quill Lake is an important Piping Plover breeding site and measures should be taken to ensure its continued protection.