A few odorous compounds found in roses are chosen to arouse the reader's interest in their molecular structures. This article differs from some similar reports on odorants mainly by combining the structural description with the presentation of the following types of isomers: constitutional isomers, enantiomers, and diastereomers. The preparation of rose oils by distillation of blossoms with water and the analysis of the oils by gas chromatography-mass spectrometry are briefly described. 2-Phenylethanol, [beta]-ionone, [beta]-damascone, [beta]-damascenone, citronellol, rose oxide, geraniol, and nerol are the most important odorous components of many rose species. Beyond these, a few additional isomers of odorants and the practical applications of fragrance materials are briefly presented. The natural or synthetic origin of an odorous compound is economically relevant, but its activity does not depend upon its origin. This article is recommended as a lesson on the relationship between molecular structure and odor for chemistry students in their second year at university. (Contains 1 table and 8 figures.)