The CD-R, a recordable disc that can be played on CD and CD-ROM drives, is emerging as the ideal device for small-scale data distribution and pre-master editing of CD-ROMs. Several media manufacturers have plans to add CD-R to their product line and need to become familiar with the new testing requirements. Testing of recordable media such as CD-R has very different aspects from the testing of CDs. The CD-R system description is given in the Orange Book, Part Two published by Sony and Philips. Since the CD-R has to be playable on a regular CD (-ROM) player it must meet both the regular Red Book specifications for CD and the additional requirements that allow recording on a CD-R drive. CD manufacturers are intimately familiar with the Red Book requirements and with the test methods used to ensure compliance. The CD-R is posing new and interesting challenges to an industry largely used to non-destructive read-only testing. In the following a review will be given of the CD-R, its specifications and testing requirements, together with testing approaches. Special attention will be given to the measurement of jitter.