Ingestion of fish is considered the main pathway of human exposure to methylmercury (MeHg), particularly for riverside populations, where fish is the main source of protein. The objective of this study was to estimate concentration of MeHg based on total concentration of mercury in muscles of three species of carnivorous fish: Boulengerella cuvieri (bicuda), Serrasalmus rhombeus (piranha), and Hydrolycus armatus (cachorra), collected from Teles Pires River, Brazil. Furthermore, we calculated human health risk related to MeHg contamination caused by fish consumption. Fish were collected in 20 field campaigns from December 2011 to September 2016 at Teles Pires River, in area of influence of Colíder hydroelectric plant. Risk index (RI) related to ingestion of MeHg through fish intake was calculated considering that MeHg corresponds to around 90% of mercury in fish. There were no significant differences in average mercury concentration between all species: S. rhombeus (0.304 mg/kg –1 ), H. armatus (0.229 mg/kg –1 ), and B. cuvieri (0.199 mg/kg –1 ). RI calculated for sensitive groups (lactating women, breastfeeding infants and children) and RI calculated for general population presented average values, suggesting adverse health effects. This first assessment on MeHg and human exposure to people from Teles Pires River area through fish consumption suggests that mercury concentrations might be posing health adverse effects on people of this sensitive group. Further studies involving more fish specimens and considering fish biological factors are needed to fully understand health risks of mercury exposure to humans in this region.