This research dataset operationalizes the measurement of precarious employment in Brazil using a fuzzy set methodology. The data structure accounts for a complex survey design, incorporating variables for Primary Sampling Units (upa), strata (stratum), and individual/household weights (weight) to ensure statistical validity. Its core analytical variables are membership grades that quantify the degree of precarity across three distinct dimensions: income inadequacy (mu_fm), employment insecurity (mu_fs1), and the lack of rights and protections (mu_fs2). These component measures are then synthesized into a final composite indicator, the Fuzzy Precarious Employment Index (fpei), structuring the dataset for quantitative cross-sectional and longitudinal analysis of employment conditions at national, regional (region), and state (state) levels.