Mid-infrared spectroscopy in the transmission mode was used to predict inorganic nitrogen (N), organic N, and total N in soil leachate. The developed predictions were accurate and robust for total N, NH₄⁺, NO₃^-, inorganic N (NH₄⁺ + NO₃^-), and organic N (total N - inorganic N) with high determination coefficients (R² = 96.7 - 99.0) and residual prediction deviation (RPD = 5.47 - 9.96). The proposed method simultaneously estimates the concentrations of dissolved nitrogen species in soil leachates accurately and with significant savings in time, cost, and chemicals relevant to conventional methods.