The negative impact of N over-fertilization has acquired importance in rose (Rosa spp.) growers in Colombia.The nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) has been considered a valuable alternative to diminish the N losses by leaching and to enable more efficient N use efficiency in crops.The objective of the present work was to study the effect of DMPP on the mineral N (NH4 + -N and NO3 --N) content in soil and water leaching, and physiological characteristics of rose plants.A greenhouse experiment was performed for 10 wk.Four-year-old 'Charlotte' rose cultivars grafted on 'Natal Briar' were grown in soil and fertirrigated daily with a complete nutrient solution containing 170 mg N L -1 .Two N fertilizers (uncoated urea [UA], and urea + 1% DMPP [UDMPP]) were used.Results showed that UDMPP did not show any advantages on dry mass accumulation, N use efficiency, leaf area, number of marketable stems, SPAD readings, chlorophyll fluorescence, and leaf N concentration.Despite all these results, the addition of the inhibitor reduced mean NO3 --N concentrations in the percolated water by 65.81%.These results suggest that UDMPP could be a valuable tool to reduce NO3 --N leaching losses by retaining applied N in the ammoniacal form.