An automatic milking system (AMS) was compared with a traditional milking parlor (MP) to evaluate metabolic and psycho-physiological aspects of animal welfare. Twenty Italian Friesian heifers were allocated to 2 groups of 10 cows each after calving and maintained in the same free-stall barn. The first group was milked twice daily in a MP; the second group was milked in a single box AMS. Feed and diet characteristics were analyzed. Health status and body condition score (BCS) were evaluated in each cow. Blood samples were obtained from -14 to 154 d in milk (DIM) to determine metabolic profile and basal concentrations of cortisol in plasma. Data collected from 10 cows per group were processed. No significant difference was detected in milk yield, BCS, and energy-related metabolites (glucose, nonesterified fatty acids, beta-hydroxybutyrate, and triglycerides) from cows in MP or in AMS during the first 22 wk of lactation. These results, jointly with the absence of significant differences in plasma metabolites related to protein metabolism, mineral metabolism, and liver function during the first 22 wk of lactation, indicates that cows in AMS did not suffer metabolically. Greater basal concentrations of plasma cortisol in AMS cows, even if absolute values were considered to be in an acceptable range, might indicate chronic stress in these primiparous cows. Further research is necessary to confirm this hypothesis.