Background Phone calls between pharmacists and prescribers play an important role in resolving potential errors and other issues. Despite their importance in patient care, and sometimes causing frustration for pharmacists, there is little research on these calls. Objective To quantify how long calls between pharmacists and prescribers are, how often phone calls occur, why calls are made, and who is called. Method An observational study was conducted with 130.5 h observed in 11 community pharmacies over 8 weeks in Dunedin, New Zealand, recording information about all incoming and outgoing calls. Data captured included information on length, date, time, reason for call, pharmacy staff involved, health professionals involved, and the place being called. We also surveyed pharmacists' perceptions of this communication. Results Data on 95 phone calls was captured. The mean length was 110 s (95% CI 88-133), at an average of 0.7 calls per hour. The most frequent reasons for calling were clarifications and dose inquiries. Conclusion Calling prescribers is perceived as a frustrating; however the frequency of calls we observed was low, but some were long. The amount of time spent for pharmacist interventions may be reduced using alternative communication methods but these need further study.