We investigated the inorganic nitrogen uptake by cucumber (Cucumis sativus L.) plants under high-voltage electrostatic field (HVEF). The maximum uptake rates and affinities significantly changed with increasing field intensity. Ammonium uptake slightly increased when the field intensity increased to 1.0 kV cm(-1) and then decreased between 2.0 and 3.0 kV cm(-1). HVEF contributed to the affinity for nitrate in all treatment groups. The affinity of cucumber seedlings for nitrate positively correlated with the intensity of the applied field as the field increased to 1.0 kV cm(-1). HVEF enabled the seedlings to opt to consume nitrate when two types of nitrogen were present in the nutrient solution. These results can be attributed to feedback adjustment and electron transportation in nitrogen assimilation.