This report presents the findings of CORE's (Community Organized Relief Effort) Winterization Needs Assessment in Ukraine, which was conducted to assess the urgent challenges faced by households during the 2024-25 winter season and to inform effective response strategies. CORE surveyed 394 households via telephone and targeted four eastern oblasts heavily impacted by the war: Kharkivska, Zaporizka, Khersonska, and Donetska. The surveyed population was older, on average, and showed a high prevalence of disabilities and chronic health conditions. Most households were, on average, located just 20 km (12.4 miles) away from the frontline. The findings indicate that the majority of households are energy insecure and unable to meet their basic energy-related needs. Winterization priorities include energy materials, home utilities, and housing repairs. While cash assistance was the preferred modality for most needs, in-kind assistance was favored for winter energy materials and NFIs and specific population groups. CORE recommends a multi-modal response to address diverse needs and mitigate potential market disruptions.