Considering permanently increasing demands for seal materials, and because of specifications becoming stricter all the time it is absolutely necessary to deal intensively with the topic permeation of media through elastomeric materials in order to create new innovative sealing concepts. This article is divided into four parts. Within the first two parts the basics of the permeation process are briefly discussed and different measurement techniques for the characterisation of permeation of liquid and gaseous media through elastomeric compounds are presented. The third part of the article deals with material properties of different elastomer compounds and the parameters influencing permeation behaviour. The influence of the temperature, of the type of elastomer, of the concentration of filler within the compound and of the type of gas permeating through the elastomer is discussed. The last part of this article focuses on development trends considering elastomeric seal materials. An approach in order to reduce permeation through elastomeric seal materials is presented.