Bean plants (Phaseolus vulgaris L. ‘Bianco di Bagnasco’) were subjected to phosphate deprivation and both the activity of anti-oxidative enzymes and the concentration of chemical hydrogen peroxide scavengers were measured in leaves and roots extracts. P deprivation provoked a reduction of total ascorbate and total glutathione in leaves and roots; however, the content of reduced ascorbate increased in both tissues while the content of reduced glutathione decreased. The reduced availability of Pi in the plant tissues affected the activity of anti-oxidative enzymes mainly after the first days of P deprivation, particularly in leaves. It could be suggested that during this period the plant adjusts its metabolism to cope with the nutritional stress by activating several physiological responses that are modifying the level of hydrogen peroxide and of its scavenging molecules and enzymes. Therefore, P-deprivation is acting as a mild oxidative stress.