The objectives of this study are to identify the risks in green retrofit projects in Singapore; analyze their risk criticalities; compare the risk criticalities between conventional and green retrofit projects; and provide mitigation measures for the critical risks. Twenty risks and 37 mitigation measures were identified from a literature review. A questionnaire survey was performed with 30 professionals experienced in green retrofits, and five post-survey interviews were conducted. The results indicated post-retrofit tenants' cooperation risk was the top risk, and that 19 risks were more critical in green retrofits than in conventional retrofits. Additionally, 28 mitigation measures obtained significant agreement.