Background. Acute respiratory infections (ARIs) are the most common symptomatic reason to seek ambulatory care, but many ARI visits may not be necessary. Objective. To measure the proportion of primary care ARI visits that may not require an office visit. Methods. We identified 58 398 ARI visits to 14 primary care practices between May 2011 and May 2012 and randomly selected 500 visits, 439 of which were new ARI visits. We separated non-visit-required information [e.g. history of present illness (HPI), past medical history, etc.] from information that required an office visit (e.g. physical exam, testing, etc.). Reviewing non-visit-required information, we identified the diagnosis (HPI diagnosis) and whether office visit appeared necessary. Independently, we reviewed the visit-required information and determined if the visit changed antibiotic management. Results. Based on non-visit-required information, 72% (316/439) of visits did not appear to require an office visit. The most common diagnoses were non-specific upper respiratory infection (39%), sinusitis (24%) and acute bronchitis (22%). The HPI diagnosis was an exact match for clinicians' diagnosis in 67% (213/316) of visits. After reviewing the visit-required information, antibiotic management did not change for 87% (276/316) of visits. For the remaining 13% (40/316) for which the visit changed management, the clinician prescribed an antibiotic for an antibiotic-appropriate diagnosis (65%; 26/40); prescribed an antibiotic for a non-antibiotic-appropriate diagnosis (25%; 10/40); or avoided an antibiotic prescription for patients with an HPI diagnosis of sinusitis (10%; 4/40). Conclusion. About two-thirds of primary care ARI visits may not be necessary for appropriate antibiotic management.