The research is entitled “Penerjemahan Ungkapan Idiomatik dalam Novel The Chocolate Box Girls: Marshmallow Skye Karya Cathy Cassidy”. The objectives of this research are: 1) To describe types of idiom that contained in the novel “The Chocolate Box of Girls: Marshmallow Skye ”by Cathy Cassidy and 2) To describe kind of techniques are used in translating idiomatic expression in the novel “The Chocolate Box of  Girls: Marshmallow Skye” by Cathy Cassidy. The research method is descriptive qualitative method. Theories applied in this research are types of idiom theory based on O’Dell & McCarthy theory (2010) and translation techniques theory based on Molina & Albir theory (2002). Data collection technique applied in this research is read-note, whereas data analysis technique that applied is content-analysis. The result of this research shows that there are 62 idioms data found in the novel “The Chocolate Box Girls: Marshmallow Skye” as well as its translated novel. Types of idiom found are 6 types, such as Similes, Binomials, Proverbs, Euphemisms, Clichéand Fixed Statement. Meanwhile translation technique was found 5 kinds of translation techniques; CalqueCompensation, Established Equivalence, Modulation, and Transposition.