The characteristic calls of Saguinus fuscicollis are described and illustrated with sound spectrograms. Each call type and its associated behavior is listed together with motor and vocal responses usually observed for a given context. Many of the call types are highly specific to social contexts while others appear to reflect changes in excitation level. Call types form two categories when related according to their acoustic structural similarity. Information in the ‘group vocabulary’ is discussed under five functional categories: spatial cohesion; alerting; aggressive behavior; infant calls, and adult vocalization during infant ca