The National Heart, Lung, and Blood Institute developed the Honoring the Gift of Heart Health (HGHH) curriculum to promote cardiovascular knowledge and heart-healthy lifestyles among American Indians and Alaska Natives (AI/ANs). Using data from a small randomized trial designed to reduce diabetes and cardiovascular disease (CVD) risk among overweight/obese AI/ANs, we evaluated the impact of an adapted HGHH curriculum on cardiovascular knowledge. We also assessed whether the curriculum was effective across levels of health literacy (defined as the 'capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions'). We examined change in knowledge from baseline to 3 months for two groups: HGHH (N = 89) and control (N = 50). Compared with controls, HGHH participants showed significant improvement in heart attack knowledge and marginally significant improvement in stroke and general CVD knowledge. HGHH participants attending ≥1 class showed significantly greater improvement than controls on all three measures. Although HGHH participants with inadequate health literacy had worse heart attack and stroke knowledge at baseline and 3 months than did participants with adequate skills, the degree of improvement in knowledge did not differ by health literacy level. HGHH appears to improve cardiovascular knowledge among AI/ANs across health literacy levels.