Data on the blood chemistry of a chondrostean fish, the Adriatic sturgeon (Acipenser naccarii), are reported as measured with different sampling procedures, and as related to rearing conditions and age. Serum Cortisol, glucose, osmolality, Na+, Cl-, Ca2+ and total protein concentrations were measured. Reference values for the blood chemistry of farmed sturgeon were measured on samples from resting undisturbed animals collected via a chronic indwelling catheter in the dorsal aorta that was implanted under anaesthesia. Following 24h recovery from catheterization, serum Cortisol, glucose and osmolality levels were 9.4 ng/ml, 58.8 mg/dl and 261.4 mOsm/kg, respectively. Furthermore, blood samples collected with the chronic indwelling catheters indicated that the surgical procedure of cannulation caused a stress response, with physiological changes that followed a pattern like that described in teleosts. Cortisol, glucose and osmolality were more sensitive to stress than the other variables measured. Sampling by cardiac puncture tended to be associated with elevated serum Cortisol levels in older, larger sturgeon, but not in young fish. Greater capture, confinement and handling stress in older, larger, sturgeon may have been responsible for this and other age-related differences in blood chemistry values measured following cardiac puncture. Within the same age class, both rearing conditions and temperature affected Cortisol, sodium and total protein concentrations significantly. Anaesthesia did not appear to reduce the degree of stress associated with cardiac puncture but altered serum ion concentrations.