Pitfall traps were used to monitor the activity of ants in a forest floor and a one-year-old fallow plot in Ile-Ife, Nigeria, at monthly intervals between November 1980 and October 1981. Similar studies were carried out between October 1987 and June 1988. These studies also included manual collection of ants from the floor of the experimental plots. Of all the 10 species of ants recorded, Pbeihk rrassinoda was the most abundant in the forest and fallow plots both in 1980-81 and 1987-88. R rrassinoda accounted for 52 percent and 88 percent of the ant populations collected manually from the forest and fallow plots respectively between December 1987 and June 1988. This species was also significantly higher in the pitfall catches of the fallow than the forest plots. Pitfall traps were not effective in sampling the populations of the belligerent Doryfus nigricans. The data are consistent with the widely accepted notion that forested areas support less ants than unforested areas. Differences in physical habitat characteristics, food availability, nesting habits, predation and microenvironmental factors were considered responsible for the differences in activities and abundance of ants in the forest and fallow plots.