OBJECTIVES: Electronic case reporting (eCR), a cornerstone of the Centers for Disease Control and Prevention's (CDC's) Data Modernization Initiative, automates bidirectional information sharing between electronic health records and public health agencies for reportable conditions. eCR grew rapidly in response to the COVID-19 pandemic. CDC and the Florida Department of Health (FDOH) collaborated to compare the completeness and timeliness of eCR with that of traditional reporting methods for COVID-19-related patient encounters at 4 health care organizations in Florida in December 2020. METHODS: Electronic initial case reports (eICRs) were matched to corresponding (ie, for same patient encounter) electronic laboratory reports (ELRs) or manually transmitted documents. We extracted and compared selected data from each report type across matched reports for completeness and timeliness. RESULTS: Most (>98%) eICRs provided earlier notification of COVID-19 to the local public health department than corresponding ELRs or manually transmitted documents. Additionally, eICRs provided more data on race and ethnicity (>90%) than ELRs (71%) or manually transmitted documents (<5%). CONCLUSIONS: Advancing implementation of eCR nationwide may provide more complete and timely case data than ELR or manually transmitted documents to guide public health action.