Four types of markings using 3 types of paint were tested to find a satisfactory agent applicable to deer pellet groups to identify those present at the beginning of a pellet-group count period. Percentages of pellet groups with marking visible after 10 1/2 months of natural weathering at an elevation of 7300 ft. near Fort Collins, Colorado, were as follows 8 or 9 white limestone fragments placed in the center of pellet groups and sprayed with yellow traffic-striping paint, 96 [degree]/o; traffic-striping paint, 78 %; industrial paint, 14 to 73 % depending on color; implement enamel, 71 %>. Yellow was the most visible color tested, red second, orange third, and white fourth. The main factors in the deterioration of markings were high summer temperatures and the age of pellets at the time they were marked.