Objective: The aim of this study was to analyze vaccination coverage at 24 months of age among children born in 2017 and 2018, residing in Teresina, Piauí. Methods: This was an analytical, cross-sectional, household survey study, with cluster sampling of census tracts stratified according to socioeconomic conditions (A: high; B: medium; C: low; D: very low). Socioeconomic data were obtained through structured interviews with guardians, and vaccination records were obtained through photographs of the vaccination booklet. Indicators of coverage, access, adherence, and abandonment of vaccination were estimated using percentage frequencies and 95% confidence intervals (95% CI), applying sample weights. Crude (OR-b) and adjusted (OR-a) odds ratios were calculated using univariate and multivariate logistic regression to identify factors associated with vaccination incompleteness. We considered basic coverage to be the application of BCG (1 dose), Hepatitis B (1), Pentavalent (3 doses), IPV (3), VORH (2), Pneumococcal-10 (2), Meningococcal-C (2) and Yellow Fever (1). Complete coverage included the basic scheme plus MMR (2), boosters of Pneumococcal-10, Meningococcal-C, OPV and DTP (1 each), Hepatitis A (1) and Varicella (1). Results: The final sample of 899 children presented complete vaccination coverage of 63.6% (n=571; 95% CI: 55.49–71.07), being higher in stratum B (74.9%; 95% CI: 60.65–85.31). Incompleteness of the basic scheme was associated with crowded households (OR-b=2.79) and mothers with more than one child (OR-b=1.44; OR-a=2.60). For the complete scheme, it was associated with maternal multiparity (OR-b=1.19; OR-a=1.59), 9–12 years of schooling (OR-b=2.30), and family income >BRL 8,000 (OR-b=3.02; OR-a=6.25). There was a lower chance of incompleteness among children in fourth position or higher in the birth order (basic: OR-a=0.02; complete: OR-a=0.15) and among mothers with ≥16 years of schooling (basic: OR-b=0.33; OR-a=0.22). Conclusion: Insufficient and heterogeneous vaccination coverage was observed, with disparities between socioeconomic strata, between basic and complete schemes and divergence in relation to the SI-PNI data.