OBJECTIVES The purpose of this study was to compare the prognostic utility of apoB/AI, total cholesterol/HDL (TC/HDL) ratio, non-HDL cholesterol (non-HDL-C), or hs-CRP as predictors of clinical risk among patients receiving statin therapy after acute coronary syndromes (ACS). METHODS AND RESULTS Patients with ACS were randomized in the PROVE IT-TIMI 22 trial to either pravastatin 40 mg or atorvastatin 80 mg. Cox regression models adjusting for confounders were used to assess the relationship between on-treatment lipids or hs-CRP and risk of death or acute coronary events. At 4 months a 1 SD increment in apoB/AI (HR 1.10, 95% CI 1.01 to 1.20), TC/HDL (HR 1.12, 95% CI 1.01 to 1.24), and non-HDL-C (HR 1.20, 95% CI 1.07 to 1.35) predicted events to a similar extent as LDL-C (HR 1.20, 95% CI 1.07 to 1.35) with neither apoB/AI, TC/HDL, nor non-HDL-C improving risk prediction models which included LDL-C. In contrast, the addition of hs-CRP significantly improved risk prediction models irrespective of the lipid parameters included, with a 29% to 30% increased risk observed per 1 SD increment in log CRP. CONCLUSION In the present study of ACS patients receiving statin therapy, on-treatment apoB/AI, TC/HDL, and non-HDL-C offered similar prognostic information to LDL-C. However, the addition of hs-CRP to lipid-based measurements significantly improved risk prediction. On treatment CRP measurement may therefore offer additive prognostic information to lipids in ACS patients.