"U-Pace" instruction, comprised of concept mastery and amplified assistance, has shown promise in increasing undergraduate success. To evaluate the efficacy of "U-Pace" instruction for students at risk for college noncompletion and students not at risk and to determine whether concept mastery, amplified assistance, or both "U-Pace" components are responsible for the greater learning associated with "U-Pace" instruction, an experiment was conducted with four instructional conditions ("U-Pace", concept mastery, amplified assistance, and face-to-face). At a public university, 914 undergraduates (576 at risk) participated. "U-Pace" instruction produced greater learning on a proctored cumulative assessment than the comparisons. Additionally, "U-Pace" instruction produced greater academic success in terms of final course grades than face-to-face instruction. The percentage of final grades of A or B did not differ for concept mastery, amplified assistance, and "U-Pace" students. No interaction between instructional condition and risk status was found for final course grades or learning. The efficacy of "U-Pace" instruction for both at-risk students and students not at risk was supported.