Abstract The simultaneous or sequential determination of chromium(VI) and total chromium in water by flow injection analysis, using different configurations with a double- or single-beam spectrophotometer as detector, is investigated. The method is based on reaction between chromium(VI) and 1,5-diphenylcarbazide. Chromium(III) and (VI) are distinguished by using two carrier streams, one of which contains cerium(IV) to oxidize chromium(III) to chromium(VI). The determination range is 0.2–10.0 μg Cr ml −1; the r.s.d. is 0.8% for 1 μg Cr. The sampling frequency is 40 h −1. A wide study of interferences is reported.