Objectives: We assessed trends in primary care paediatric blood pressure (BP) screening, follow-up, and treatment before and during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Retrospective cohort study using electronic medical records from the Canadian Primary Care Sentinel Surveillance Network to capture paediatric visits (aged 3 to 18) between January 1, 2011, and December 31, 2020. Time-series analysis was performed using documentation of monthly BP, high BP, follow-up of abnormal BP, and antihypertensive prescribing. We assessed differences between pre (January 1, 2011 to March 11, 2020) and during COVID-19 (March 12, 2020 to December 31, 2020). Results: Of 343,191 paediatric patients, 30.9% had >= 1 paediatric BP documented. Documentation of BP increased each year from 17.3% in 2011 to 19.8% in 2019 (beta = 0.05, 95% CI 0.04, 0.07, P < 0.001), with a decrease in trend in 2020 to 11.0% (beta = -16.95, 95% CI -18.91, -14.99, P < 0.001). There was an increasing pre-pandemic trend for laboratory screening and prescribing (beta = 0.12, 95% CI 0.1, 0.14, P < 0.0001; beta = 0.02, 95% CI 0.02, 0.02, P < 0.0001). During the COVID-19 pandemic, laboratory screening further increased (24.5% to 31.1%; beta = 5.19, 95% CI 2.03, 8.35, P = 0.002), whereas there was no significant change in prescribing trends (1.3% to 1.4%; beta = 0.15, 95% CI -0.01, 0.32, P = 0.07). Conclusions: Documentation of BP increased annually, then declined precipitously during the COVID-19 pandemic. Despite lower BP screening and follow-up, the prevalence of hypertension and antihypertensive prescribing remained stable. Clinical practice trends in primary care highlight areas to improve the care and management of hypertensive paediatric patients. [GRAPHICS] .