Background: The Child and Adult Care Food Program (CACFP) serves nutritious meals/snacks to >3.6 million children in early childhood education (ECE) centers. This study provides a nationwide assessment of nonhome-based CACFP-participating ECE centers' awareness of and reported readiness for implementing updated CACFP standards/best practices that took effect October 1, 2017. Methods: A national frame of 38,760 centers serving children ages 0-5 was developed. A web-based survey of 5483 sampled centers, stratified by census division, was conducted between August 22 and September 30, 2017. One thousand three hundred forty-three centers (25%) located in 47 states and the District of Columbia responded. Surveys were primarily completed by center directors/assistant directors (71%). Nonresponse adjusted multivariate regressions were conducted, controlling for center/zip code-level characteristics. Results: The majority of centers reported being "very" familiar with the updated standards and met specific standards/best practices. Centers that reported being "somewhat" (vs. "very") familiar with the standards were less prepared and likely to have begun implementation and more likely to need additional time, money, and staff. Centers that reported being "not"/"somewhat" familiar (vs. "very") with the updated standards were also less likely to meet specific standards/best practices. Center preparedness and standards/best practices varied by weekly rates/fees charged. Centers in the West (vs. South) were more likely to report meeting sugary cereal standards and fruits and vegetables as a snack component best practice. Conclusions: While most centers reported familiarity with and were prepared to implement the updated CACFP standards, readiness is not universal. Technical assistance and training should ensure that all centers are trained on the updated standards. (author abstract)