OBJECTIVE: Insulin resistance is associated with autonomic dysfunction. An attenuated decrease in heart rate after exercise (or heart rate recovery [HRR]) predicts all-cause mortality and is believed to reflect decreased parasympathetic activity. Utilizing triglyceride/HDL cholesterol concentration as a marker of insulin resistance, we sought to assess the association between insulin resistance and HRR. RESEARCH DESIGN AND METHODS: Our study population included 4,963 healthy adults who participated in the Lipid Research Clinics Prevalence Study and underwent exercise testing. HRR was considered abnormal if it did not drop > or = 42 bpm 2 min after completion of exercise. Fasting blood specimens were drawn. RESULTS: Individuals in the highest quartile of triglyceride/HDL cholesterol had a significantly higher prevalence of abnormal HRR (40 vs. 30%, multivariable-adjusted prevalence ratio 1.18, 95% CI 1.01-1.39; P = 0.04). As a continuous variable, an increase in 1 SD of triglyceride-to-HDL cholesterol ratio was associated with a greater likelihood of an abnormal HRR, even after adjusting for >20 covariates (adjusted OR 1.16, 95% CI 1.07-1.25; P < 0.001). During 12 years of follow-up, there were 284 deaths. In age- and sex-adjusted analysis, participants with an abnormal HRR and high triglyceride-to-HDL cholesterol ratio had significantly higher mortality than those with a normal HRR and high triglyceride-to-HDL cholesterol ratio (hazard ratio = 1.49, 95% CI 1.08-2.04; P = 0.015). CONCLUSIONS: HRR is associated with triglyceride-to-HDL cholesterol ratio and identifies patients with insulin resistance who are at increased risk of death.