A fast photokinetic method for the determination of Fe(III) is reported, which employs photoreduction of Fe(III),in situcomplexation of the Fe(II) produced, and continuous recording of the absorbance of the colored complex. Complete photoconversion is not necessary; the total photolysis time is approximately one minute. Linear calibration plots were obtained using the initial slope method over the range 2 to 10 micromoles of Fe(III) with relative standard deviation of 1.5%.