A sensitive and fast flow-injection spectrophotometric method for the determination of ofloxacin is proposed. The method is based on the formation of a yellow complex between ofloxacin and Fe (III), in sulphuric medium. The influence of FI and chemical variables were studied. The calibration graph resulting from measuring the absorbance at 420 nm is linear over the range 5.0 x 10(-6)8.0 x 10(-4)M (1.8-289 mg l(-1)) with a detection limit of 2.0 x 10(-6)M (0.72 mg l(-1)). The method is applied to the routine analysis of ofloxacin in pharmaceuticals and human urine.