Introduction The ability to provide primary care with the help of a digital platform raises both opportunities and risks. While access to primary care improves, overuse of services and medication may occur. The use of digital care technologies is likely to continue to increase and evidence of its effects, costs and distributional impacts is needed to support policy-making. Since 2016, the number of digital primary care consultations for a range of conditions has increased rapidly in Sweden. This research project aims to investigate health system effects of this development. The overall research question is to what extent such care is a cost-effective and equitable alternative to traditional, in-office primary care in the context of a publicly funded health system with universal access. Three specific areas of investigation are identified: clinical effect; cost and distributional impact. This protocol describes the investigative approach of the project in terms of aims, design, materials, methods and expected results. Methods and analysis The research project adopts a retrospective study design and aims to apply statistical analyses of patient-level register data on key variables from seven regions of Sweden over the years 2017-2018. In addition to data on three common infectious conditions (upper respiratory tract infection; lower urinary tract infection; and skin and soft-tissue infection), information on other healthcare use, socioeconomic status and demography will be collected. Ethics and dissemination This registry-based study has received ethical approval by the Swedish Ethical Review Authority. Use of data will follow the Swedish legislation and practice with regards to consent. The results will be disseminated both to the research community, healthcare decision makers and to the general public.