Abstract A method for the measurement of iodine in feces is described. A pellet of dried, homogenized feces is treated by combustion in a bomb calorimeter and the liberated iodine absorbed in a solution of sodium hydroxide. Colorimetric determination of the iodine can then be carried out. Recovery experiments with radioactive iodine I 131 and I 125 and potassium iodate indicate a percentage recovery of 90 per cent or more. This method has been found useful in nonradioactive iodine balance studies and has an advantage over previous methods in that it is fairly quick and can be done routinely and accurately, which is essential in metabolic experiments.