A rapid procedure has been developed in which an anion-exchange resin and spectrophotofluorometry are used to determine total porphyrins in urine. After porphyrins are eluted from the resin with 3N HCl, their fluorescence at 646 nm is measured with an Aminco-Bowman Spectrophotofluorometer. About 10 min are required per analysis by a skilled technician. Added to urine specimens, 95.3 ± 4.9% of uroporphyrin and 94.7 ± 9.6% of coproporphyrin, were accounted for. Eighteen normal urine samples contained an average of 0.063 µmol of porphyrin per liter (range, 0.028-0.176 µmol/liter). The coefficient of variation, 2.9%, indicates the precision to be very satisfactory.