Elevated maternal glucocorticoid levels during pregnancy may influence fetal development and postnatal physiology of offspring. The aim of this study was to evaluate the effects of prenatal and neonatal dexamethasone exposure on hematological parameters in piglets. The experiment was conducted on 24 clinically healthy Large White Polish sows randomly assigned to two prenatal treatment groups: dexamethasone-treated (DEX) or physiological saline-treated controls (PhS). Piglets were subsequently allocated to four experimental groups according to prenatal and neonatal exposure (PhS/PhS, PhS/DEX, DEX/PhS, DEX/DEX) in a 2 × 2 factorial design. Blood samples were collected from six piglets per treatment group at each sampling time point (postnatal days 3, 14, and 30). Significant main effects of prenatal and neonatal dexamethasone exposure were observed in several erythrocyte parameters. On day 3, both prenatal and neonatal dexamethasone significantly increased RBC (p<0.001) and decreased MCV and MCH (p<0.001), with a significant interaction between factors. On day 14, neonatal dexamethasone increased RBC, HCT, and Hb values (p≤0.030), whereas prenatal exposure significantly affected MCHC and MCH (p≤0.010). By day 30, dexamethasone exposure was associated with lower Hb, HCT, MCH, and MCHC values (p≤0.010), indicating microcytic and hypochromic erythrocyte changes. White blood cell counts were not consistently affected by the treatments. These findings demonstrate that prenatal and neonatal glucocorticoid exposure modifies early erythropoietic development in piglets and influences hematological adaptation during the suckling period.