In order to completely evaluate ammonia emission from greenhouse vegetable fields, crop canopy absorption should not be neglected.  The foliar uptake of NH₃ applied at two growth stages and the subsequent ¹⁵N-labeled N translocation to other plant components were investigated under greenhouse conditions using chambers covered with the soil of a tomato field.  Treatments comprised three NH₃-N application rates (70, 140, and 210 mg/plot) using 15N-labeled ammonium sulfate.  Plants were harvested immediately after exposure for 24 h, and the total N concentrations and 15N/14N ratios were determined.  With increased NH₃ concentration, total ¹⁵NH₃-N absorption increased considerably, whereas the applied ¹⁵NH₃-N uptake decreased gradually.  The tomato plants absorbed 33–38% and 24–31% of the ¹⁵NH₃-N generated at the anthesis and fruit growth stages, respectively.  A total of 71–80% of the recovered NH₃ was observed in the leaves and 20–30% of the recovered NH₃ was remobilized to other components.  Among them, an average of 10% of the absorbed ¹⁵NH₃-N was transferred into the tomato fruits.  All these results indicated the potential of the tested tomatoes for the foliar uptake of atmospheric ¹⁵NH₃ and the distribution of 15N-labeled vegetative N among different plant components.  The results are of great importance for the complete evaluation of nitrogen use efficiency in the greenhouse tomato fields.