Observations onCebus capucinus in 10 forests in Chiriqui, Panama, are reported. Troop size ranged from two to five in small forests to 20 or more in large forests. A 10 week study was conducted in a coastal forest that contained a troop of 27 to 30Cebus. The troop’s daily path length was approximately 1.6 to 2.5 km and their home range was between 32 and 40 ha. TheCebus usually spent 50 to 70% of their day foraging and traveling. On one occasion, aCebus attacked anIguana, wrestled with it, eventually broke off 30 to 40 cm of its tail, and ate meat from the tail. The relations betweenCebus andSaimiri oerstedii, Alouatta palliata, and man are described.