The present work evaluated the concentration of total soluble phenolic compounds (TSPCs) and antioxidantactivity (AOA) of rice grains with light brown, red and black pericarp colors and the processing effect on the concentration of TSPCs in the grain. Brown rice grains of ten ecotypes and six cultivars with red pericarp, onewith a black pericarp and one with a light brown pericarp color, were evaluated. The concentration of TSPCsand AOA of rice grains with different processing (brown, polished, parboiled brown and parboiled polished)was determined, and the concentration of TSPCs was also determined in raw and cooked grains. Significantdifferences were observed in the concentrations of TSPCs and AOAs among genotypes with higher valuesobtained for grains with red and black pericarp colors, and a positive and significant correlation betweenthese parameters was found. Parboiling reduced the TSPCs concentration in the grains due to the loss ofpart of them in the processing water, thermal decomposition and, possibly, interaction with other compo-nents. This reduction is related to the lower AOA in these grains. In a similar way, cooking also reduced theconcentration of TSPCs, especially in brown and polished grain