There is a paucity of empirical studies dealing with benefits of gifted programming in mathematics for elementary students. The current study reports on the impact of using cluster grouping and specific curriculum to support gifted learners' math achievement in urban elementary schools. Although the results of Year 3 provide the most compelling evidence of success, Year 1 results are included to explain the route taken to achieve those results. The results demonstrated that teachers in a large urban school district can promote academic gains over time for gifted and comparison students provided the curriculum is designed to support learning at varied ability levels, that teachers have sufficient experience with the content to deliver the planned materials appropriately, and that the context of the classroom setting supports collaborative learning and embraces challenge for all learners. (Contains 4 tables.)