Telemedicine use expanded greatly during the COVID-19 pandemic, and broad use of telemedicine is expected to persist beyond the pandemic. More evidence on the efficiency and safety of different telemedicine modalities is needed to inform clinical and policy decisions around telemedicine use. To evaluate the efficiency and safety of telemedicine, we compared treatment and follow-up care between video and telephone visits during the COVID-19 pandemic. Observational study of patient-scheduled telemedicine visits for primary care. We used multivariate logistic regression to compare treatment (medication prescribing, laboratory/imaging orders) and 7-day follow-up care (in-person office visits, emergency department visits, and hospitalizations) between video and telephone visits, adjusted for patient characteristics. Among 734,442 telemedicine visits, 58.4% were telephone visits. Adjusted rates of medication prescribing and laboratory/imaging orders were higher in video visits than telephone visits, with differences of 3.5% (95% CI, 3.3%-3.8%) and 3.9% (95% CI, 3.6%-4.1%), respectively. Adjusted rates of 7-day follow-up in-person office visits, emergency department visits, and hospitalizations were lower after video than telephone visits, with differences of 0.7% (95% CI, 0.5%-0.9%), 0.3% (95% CI, 0.2%-0.3%), and 0.04% (95% CI, 0.02%-0.06%), respectively. Among telemedicine visits with primary care clinicians, return visits were not common and downstream emergency events were rare. Adjusted rates of treatment measures were higher and adjusted rates of follow-up care were lower for video visits than telephone visits. Although video visits were marginally more efficient than telephone visits, telephone visits may offer an accessible option to address patient primary care needs without raising safety concerns.