Here we present data on polyspecific associations for several social groups within our primary study grid. The focal subjects were two groups of Procolobus badius (bad1 and bad2) and two groups of Cercopithecus diana (dia1 and dia2). Association data on the Procolobus badius groups were collected between June 1996 and May 1998 while association data on the Cercopithecus diana groups were collected between April 1997 and May 1998. On most observation days we followed a focal group from 7:00 h to 17:30 h. Data on association behavior were collected at every one-hour interval and one hourly group scan represents a single data point. During each hourly scan, we recorded the number of species “in association” with the focal species. Groups of different species were considered associated when the distance between imaginary polygons connecting the most outermost members of each group was less than 25 m. Association rates were calculated by dividing the time each group was seen “in association” with another species by the total observation time. In late 1997 both Procolobus badius groups divided into subgroups, each of which had a preferred Cercopithecus diana association partner.