To meet energy demands for lactogenesis and to sustain homeostatic conditions post-partum, the organism of breastfeeding mother undergoes combined endocrine and metabolic regulation. The main objective of this study was to determine basal serum concentrations of hormones involved in the maintenance and defense of energy balance in breastfeeding (BF) and formula feeding (FF) mothers. Twenty healthy exclusively breastfeeding mothers at 3rd month of lactation (EBF3), 17 healthy partially breastfeeding at 6th month of lactation (PB6) and 17 healthy FF mothers participated in this study. Fasting serum prolactin (PRL), acylated ghrelin (aGhr), total ghrelin (tGhr), leptin, adiponectin, insulin, and cortisol were determined for all study participants and correlations between studied parameters were calculated for BF women. We found significantly lower basal insulin (p = 0.0048) and cortisol (p = 0.0002) and significantly elevated basal prolactin (p = 0.0020) and leptin (p = 0.0416) in BF when compared with FF women. The differences were not associated with the duration of lactation (3 vs. 6 months), except for PRL, which was highest in EBF3. Levels of Ghr and adiponectin did not differ between study groups. In the BF group, the negative correlations were found between: aGhr and insulin, aGhr and adiponectin, leptin and cortisol, leptin and adiponectin, insulin and adiponectin, cortisol and adiponectin. Positive associations were noted between: insulin and leptin, leptin and aGhr, PRL and leptin, PRL and aGhr. Leptin and insulin correlated positively, whereas adiponectin negatively with BMI. These data may suggest that EBF3 and PB6 as compared with FF mothers, exhibit hormonal regulation which tends to be more advantageous for their metabolic profile and is not related to the duration of breastfeeding within the first 6 months of lactation.