An investigation was made of the applicability of the chromium oxide-indicator method to a study of the digestibility of rations self fed to pigs on a lot basis. It was found that digestion coefficients derived from from the chromium oxide concentrations of the feed and feces were in close agreement with those determined in total collection trials. The concentration of chromium oxide in the feces of pigs self fed rations containing chromium oxide became relatively constant between three and four days after the initial feeding. The rates of recovery of chromium oxide from individual samples of feces taken at various times (5:30 a.m., 10:30 a.m., 3:30 p.m. and 8:30 p.m.) of the day were significantly different. However, the average digestion coefficients derived from the analysis of samples taken at each of these times of four consecutive days were different from those determined by the total collection of the feces by only one percentage unit. Digestion coefficients computed from the mean concentrations of chromium oxide in fecal samples taken from pigs individually during one-day periods agreed closely with those determined in a total-collection trial of 7-day duration. Although the estimates of digestibility derived from the chromium oxide content of feces taken rectally from individual pigs at 6 a.m. and 5 p.m. and compounded on a lot basis for a one-day period did not agree as closely with the digestion coefficients determined in the 7-day, total-collection trial as the estimates made in the other sampling procedures, even these were fairly accurate. A highly significant difference was found among the digestion coefficients determined with individual pigs self fed the same ration in one lot.