A spectrofluorimetric method for the determination of trace amounts of tungsten was developed, based on ion-exchange spectrofluorimetry. Tungsten reacts with carminic acid to give a red fluorescent complex, which was fixed on a dextran-type anion-exchange resin. The fluorescence of the resin, packed in a 1-mm quartz cell, was measured directly using a solid-surface attachment. The applicable concentration range was 1.0–20.0 µg l^–1, with a relative standard deviation of 1.5% and a detection limit of 0.3 µg l^–1. The method was applied to the determination of tungsten in natural waters. The method is more sensitive and selective than that using carminic acid alone.