The coordinated differentiation of hematopoietic stem and progenitor cells into the various mature blood cell types is responsible for sustaining blood and immune system homeostasis. The cell fate decisions underlying this important biological process are made at the level of single cells. Methods to trace the fate of single cells are therefore essential to understanding the hematopoietic system activity in health and disease. In this ISEH New Investigator webinar, we will hear from three technical experts about some of the most powerful methods available to trace cell fate in the hematopoietic system; Joana Carrelha from the University of Oxford, Dawn Lin from the Walter and Eliza Hall Institute of Medical Research, and Alejo Rodriguez-Fraticelli from Harvard University, with moderation by Simon Haas from Heidelberg Institute for Stem Cell Technology and Experimental Medicine. This webinar will cover the basic methodologies and technical considerations for single cell transplantation assays, lentiviral barcoding technologies, and sleeping beauty barcoding.