Cardiovascular safety has become a very important component of contemporary drug development.  Safety assessments are conducted throughout a drug’s nonclinical and clinical development programs, and they continue once a drug has received marketing approval.  In this paper, Dr Turner, a member of Quintiles’ Cardiac Safety and Cardiovascular Centers of Excellence, discusses why it is important that scientists involved in clinical safety assessments have a solid understanding of assessments conducted previously during nonclinical development.  Nonclinical assessments are then described at an appropriate level of detail for clinical scientists.