A toxicologic and dermatologic review of 2-heptylidenecyclopentan-1-one when used as a fragrance ingredient is presented. 2-Heptylidenecyclopentan-1-one is a member of the fragrance structural group ketones cyclopentanones and cyclopentenones. The common characteristic structural element of the group members is a cyclopentanone or cyclopentenone ring with a straight or branched chain alkane or alkene substituent. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-heptylidenecyclopentan-1-one were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and repeated dose data. A safety assessment of the entire ketones cyclopentanones and cyclopentenones will be published simultaneously with this document; please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all ketones cyclopentanones and cyclopentenones in fragrances.