OBJECTIVE To explore the types of communication used within primary health care teams (PHCTs), with a particular focus on the mechanisms teams use to promote optimal clinical and administrative information sharing. METHODS A descriptive qualitative study. METHODS Primary health care teams in Ontario between August 2004 and October 2005. METHODS Purposive sampling was used to recruit 121 members from 16 PHCTs reflecting a range of health care professionals, including family physicians, nurse practitioners, nurses, pharmacists, dietitians, social workers, office managers, health promoters, and receptionists. METHODS Individual in-depth interviews were conducted. An iterative analysis process was used to examine the verbatim transcripts created from the interviews. Techniques of immersion and crystallization were used in the analysis. RESULTS Analysis of the data revealed that communication occurs through formal and informal means. Formal communication included regular team meetings with agendas and meeting minutes, memorandums, computer-assisted communication, and communication logs. Informal communication methods were open and opportunistic, reflecting the traditional hallway consultation. For patient care issues, face-to-face communication was preferred. Team member attributes facilitating communication included approachability, availability, and proximity. Finally, funding issues could be an impediment to optimal communication. CONCLUSIONS Primary health care is experiencing demands for enhanced and efficient communication that optimizes team functioning and patient care. This study describes formal and informal mechanisms of communication currently used by PHCTs. Attributes that facilitate team communication, such as approachability, availability, and proximity of team members, were highlighted. New funding arrangements might alleviate concerns about remuneration for attendance at meetings.