Introduction: Soccer players may experience hematological changes that could be detrimental to their health status. In addition, inadequate body composition may impair performance. Objective: To assess body composition and hematological changes over a year in soccer players. Methods: A retrospective observational study was conducted. Age, weight, height, body composition, blood count, serum iron, serum ferritin, serum transferrin and total iron binding capacity data were collected from the athletes’ medical records in the months of January, May and August of 2015 and January of 2016. Body mass index was also calculated. For the statistical analyses, the Anova and post-hoc Tukey’s post-hoc tests were used for the quantitative variables and the Chi-square test for the qualitative variables. The significance level adopted was p<0.05. Results: Data were evaluated for 51 athletes with a mean age of 23.53 ± 3.11 years, 77.10 ± 6.56 kg, 1.80 ± 0.07 and 15.6 ± 2.89% body fat (BF). We observed significant (p<0.05) changes in mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, cell size and eosinophils during the period evaluated. Among the athletes, 21.6% had decreased hematocrit levels and 3.9% had hemoglobin levels below the reference range. A BF% greater than 16% was significantly related to serum iron depletion (p = 0.01). Conclusion: Small significant hematological changes during the competitive year were observed, but without significant changes in body composition. Level of Evidence III; Study of nonconsecutive patients; without consistently applied reference ‘‘gold’’ standard.