The data contains variables related to the diversity and structure of plant communities of cattle-grazed and burned old-growth grasslands and ungrazed and unburned old-growth grasslands located in the northern region of the Cerrado, specifically in the municipality of São Félix do Tocantins, state of Tocantins, Brazil, collected in March and April 2022. Data were collected in 100 plots of 1-m² distributed over ten old-growth grasslands (10 plots per site), of which five were grazed and burned and five ungrazed and unburned.