The cycloalkanes most commonly found in nature, viz., in some alkaloids, steroids and terpenoids contain six membered rings because they can exist in a completely strain free chair conformation. The fundamental understanding of the conformations of cyclohexane and the structures of molecules containing cyclohexane ring was developed by Derek H R Barton and Odd Hassel, who shared the Nobel Prize in 1969. An enormous amount of experimental and theoretical evidence is available on the conformational analysis of these compounds. In this article, distinguishing the conformations of the diastereomers and their relative stabilities are discussed in brief.