© 2019 The Japan Society for Analytical Chemistry. An cation-exclusion/anion-exchange chromatography (IEC/AEC) with conductimetric/UV-spectrophotometric detections for simultaneous determinations of the ionic nutrients (NO–3, NO–2, NH+4, HPO2–4 and K+) required for important elements for plant growth was studied on a hydrophilic polymer-based strongly basic anion-exchange resin column and a dilute NaOH eluent. Under the optimized eluent conditions (3.5 mM NaOH at 0.6 mL/min), the simultaneous separation and detection of the anions (NO–3, NO–2, HPO2–4, Cl–, SO2–4) and the cations (K+, NH+4) was achieved in ca. 25 min. The analytical performances, including the calibration graph, linearity range, correlation coefficient, detection limit, reproducibility, and recovery tests, were evaluated under the optimized chromatographic conditions. Consequently, the usefulness of the present method for monitoring plant growth nutrients in practical liquid fertilizer samples was demonstrated for understanding not only the composition of the inorganic ionic nutrients, but also the composition of inorganic ionic nitrogen by applying the IEC/AEC.