Resumo. Differences in seed morphology may indicate variability within and among plant populations. Seeds of Annona reticulata Vell., Annonaceae were biometrically characterized, came from the Rio Brilhante region, Mato Grosso do Sul state, in a fragmented area of Cerrado biome, in which the seeds were collected randomly from six different individuals. It was investigated a sum of 150 seeds, isolated into three clusters of 50 seeds. Using the statistical theory of small samples, were assessed the biometrical and physical variables of seeds regarding the length, width, thickness, seed volume index, geometric diameter means, equivalent and arithmetic, surface area, volume, sphericity and aspect ratio of the seeds. The results were compared with the Student’s t test, Kolmogorov-Smirnov’s test, and Spearman’s correlation coefficient (p<0,001). It was found that the amplitude fluctuations show a bigger proximity between the means of geometric and equivalent diameters (p>0,005), and a greater distance to the arithmetic diameter mean of Annona reticulata seeds. The seed volume index, the geometric diameter means, equivalent and arithmetic, surface area and seed volume showed correlation with all evaluated parameters. The observed variations suggest that seeds are not alike in their linear dimensions, which can be associated with morphological variability of the studied seeds.