Objective: We evaluated the extent to which providing training and technical assistance to early childcare centre (ECC) directors, faculty and staff in the implementation of evidence-based nutrition strategies improved the nutrition contexts, policies and practices of ECC serving racially and ethnically diverse, low-income children in Broward County, Florida, USA. The nutrition strategies targeted snack and beverage policies and practices, consistent with Caring for Our Children National Standards. Design: We used the nutrition observation and document review portions of the Environment and Policy Assessment and Observation (EPAO) instrument to observe ECC as part of a one-group pre-test/post-test evaluation design. Setting: ECC located within areas of high rates of poverty, diabetes, minority representation and unhealthy food index in Broward County, Florida, USA. Subjects: Eighteen ECC enrolled, mean 112.9 (SD 53.4) children aged 2-5 years; 12.3 (SD 7.2) staff members; and 10.2 (SD 4.6) children per staff member at each centre. Results: We found significant improvements in centres' overall nutrition contexts, as measured by total EPAO nutrition scores (P = 0.01). ECC made specific significant gains within written nutrition policies (P = 0.03) and nutrition training and education (P = 0.01). Conclusions: Our findings support training ECC directors, faculty and staff in evidence-based nutrition strategies to improve the nutrition policies and practices of ECC serving racially and ethnically diverse children from low-income families. The intervention resulted in improvements in some nutrition policies and practices, but not others. There remains a need to further develop the evaluation base involving the effectiveness of policy and practice interventions within ECC serving children in high-need areas. (author abstract)