Using the quantitative methods of Schwartz, Sborov, and Watson, as modified by Balikov, normal ranges for excretion of urobilinogen have been determined for adults. The individual values fall into a logarithmic type of distribution. The normal range for urine urobilinogen excretion is from 0.05 to 2.5 mg./24 hours, with a median of 0.36. The excretion of fecal urobilinogen ranges from 57 to 200 mg./24 hours for males and from 8 to 150 mg. for females. The medians for these groups are 101 and 40 mg., respectively.