It is generally recommended to adjust feeding requirements to avoid overconditioning of dairy cows at calving because high body condition is a major risk factor for ketosis in early lactation. However, beside feeding and environmental factors individual disposition for high body condition appears to have also a genetic and epigenetic background. The individual reactivity of the hypothalamic-pituitary-adrenal axis (HPA-axis) and the release of cortisol as tested in the ACTH-test varies considerably between cows. Thus, the aim of the study was to test the relationship between HPA-axis reactivity and body condition in dairy cows during the transition period. In 22 pluriparous German HF dairy cows, kept in freestalls with cubicles and fed a TMR based on grass and corn silage and concentrate, an ACTH challenge was performed on d 100 postpartum (pp). Before and after injection of ACTH (80µg) cortisol concentrations were measured in blood samples taken in short-term intervals from indwelling jugular vein catheters from which baseline and peak concentrations and AUC were assessed. Results were used in a regression analysis (SAS statistical package) and correlated with sonographically estimated subcutaneous fat mass (SC fat) assessed at d –42 before parturition, and at d 1, d 21, d 100 pp. Cows were also classified according the AUC cortisol results into high (HR; n = 7), intermediate (IR; n = 8), and low (LR; n = 7) responder and fat mass was tested for differences by ANOVA. Significant linear negative correlations were found between AUC and peak cortisol concentrations from ACTH challenge and SC fat at d –42, d 1, d 21 and d 100. In HR compared with LR cows in average SC fat was significantly less at d –42, d 1, d 21 and d 100 and gain before and loss of SC fat after parturition was lower. Cows with high reactivity of the HPA-axis are leaner during the whole transition period, gain less before and lose less SC fat after parturition. Dynamics in body condition appears to be closely correlated with HPA axis reactivity during the transition period in dairy cows. This work was funded by the German Research Foundation.