Cell lines are used extensively in research and drug development as models of normal and cancer tissues. However, a substantial proportion of cell lines is mislabelled or replaced by cells derived from a different individual, tissue or species. The scientific community has failed to tackle this problem and consequently thousands of misleading and potentially erroneous papers have been published using cell lines that are incorrectly identified. Recent efforts to develop a standard for the authentication of human cell lines using short tandem repeat profiling is an important step to eradicate this problem.