Polyphenolic compounds seem to be related to the health benefits produced by the cocoa due to their antioxidant properties. Cupuassu powder, prepared from Theobroma grandiflorum seeds, is a very promising cocoa powder substitute. In order to assess the potential health benefits of the cupuassu powder, a comparison was performed between cocoa, chocolate, and cupuassu powders in relation to the content of total phenolic compounds, flavonoids and DPPH scavenging capacity of methanolic extracts. Cupuassu "chocolates" (milk, dark, and white) were also analyzed. Mineral, lipid, protein, and moisture determinations were made in cocoa and cupuassu powders and in cupuassu "chocolates". Results showed that the phenolic contents of cocoa and chocolate powders are more than three times higher than those of cupuassu powder; however, flavonoid contents were significantly lower. The DPPH scavenging capacity varied hugely among the different samples, from 0.5 (white cupuassu "chocolate") to 120 (cocoa powder) μg of Trolox equivalent per 100 g (FW), and presented a significant correlation (r = 0.977) with the total phenolic contents but not with the flavonoid contents (r = -0.035).