The effects of different surfaces on the foraging efficiency of Solenopsis invicta workers were observed. The results indicated that the foragers of S. invicta were more efficient when they foraged on hard and smooth plastic surfaces than on soil surfaces. Similarly, foragers of S. invicta were less efficient when they encountered obstacles such as gravel or grass. The foraging activities of the S. invicta workers were considerably less on grass than on gravel, and fire ant workers from wild colonies were more efficient than workers from one-year-old laboratory colonies.