Background: The COVID-19 pandemic imposes significant impact on daily activities with regard to public health orders and individual responses to the pandemic. Much of the direct or indirect impact is potentially in reductions in healthcare encounters for services such as preventive care. Here, we quantified changes in cancer screening rates to better understand the impact of the evolving COVID-19 implications and shifts in health-seeking behaviors. Methods: We conducted a retrospective analysis of cancer screening rates during March-June 2019 (pre-COVID-19) and March-June 2020 (post-COVID-19 restrictions), using Optum’s de-identified Clinformatics Data Mart Database which includes Medicare and commercially insured members. Members meeting age and/or sex criteria as detailed in the United States Preventive Services Task Force recommendations for breast, colorectal, lung, prostate, and cervical cancer screening represented the eligible membership for screening. Procedure and laboratory services were used to identify those who received cancer screening. Analyses were conducted cross-sectionally by cancer screening type. Results: Eligible cohorts were identified from insured members within March-June 2019 and 2020 (2019: 17,931,318; 2020: 17,521,411). The percent of eligible members screened in March-June 2019 was 19.3%, 9.4%, 16.7%, 0.4%, and 7.8% for breast, cervical, prostate, lung, and colorectal cancer, respectively. Changes in screening rates from 2019 to 2020 are summarized in Table, with the sharpest decline in April. The percent change from 2019 to 2020 during the combined March-June period for each cancer screening type was statistically significant (p<0.0001). Conclusions: Routine cancer screening rates from March-June 2020 showed meaningful reductions when compared to the same period in 2019, with substantial declines during the initial peak of the pandemic in April. These declines may be impacted by variations in regional restrictions with tighter restrictions leading to larger screening declines and loosening restrictions reflecting catch-up screening. Efforts to promote cancer screening in a safe and timely manner are crucial given individual risk factors, to reduce later stage cancer diagnoses and improve clinical outcomes.