The Mental Impact and Distress Scale: COVID-19 (MIDc) was constructed and validated by one of the first pandemic-impact research teams in February 2020 and aims to assess psychosocial impacts of the COVID-19 pandemic. The purpose of the present research was to determine the psychometric properties of the MIDc's Brazilian form and outline a sociodemographic profile of the pandemic's psychosocial impact in a Brazilian sample. Altogether, 1004 Brazilians living in different regions of Brazil completed an online survey. The adapted Brazilian version presented significant validity and reliability as assessed by exploratory and confirmatory factor analysis, Cronbach alpha and Spearman-Brown coefficients, and associations with related psychological measures. Even though the Brazilian version differs from a previous (Macau) version, it contains both anticipation (i.e., the mental engagement processes of managing the unknowns) and modulation (i.e., the mental processes of insulation being activated to maintain a sense of normalcy) factors. Findings indicate greater vulnerability to modulation among younger and female participants. Black participants and those with lower family income were more prone to be economically impacted. Participants living in isolation were more vulnerable to anticipation. Thus, the COVID-19 pandemic was found to differentially affect gender, ethnic, and social groups in Brazil.