The measurement and use of minimal residual disease (MRD) is an exciting development in the world of hematological oncology. So, what is MRD, how can it be measured, why is it important, and how can it be used in the clinic? Here, Ola Landgren, MD, PhD, from Memorial Sloan Kettering Cancer Center, NY, discusses this exciting topic and answers these key questions surrounding its use. This video was recorded at the 23rd congress of European Hematology Association (EHA) 2018, held in Stockholm, Sweden.