Abstract: This paper presents data on the population of Bonnet Monkeys (Macaca radiata Geoffroy) in different parts of Bangalore city. In all 20 sectors or postal zones were surveyed from August 1964 to January 1965. There is no other species of monkey in Bangalore, with one exception in the cubbon Park troop which has accepted a Rhesus female, probably an escape from capitivity. The objects of the population survey were to gather data on the abundance and distribution of bonnet monkeys, and group-size and composition, to ascertain the ecological factors responsible for the distribution and troop size and to study food and habitat preferences