Recent developments of transplantation for the cure of paediatric leukaemias and solid tumours have led to increased interest in cord blood (CB) as an advantageous source of haematopoietic stem cells (HSC). Cord blood stem cells have unique biological properties: primitivity, a high proliferative capacity, a high level of telomerase, with a wide differentiation potential towards all haematopoietic lineages. Very recently, the wide differentiative potential of embryonic stem cells (ESC) towards a variety of tissues has led to a renewed interest into the possibility of producing tissues in vitro which are useful for replacing affected tissues and organs for the treatment of many conditions (cardiac infarction, hepatic failure, diabetes, osteoporosis). However, the use of human ES (raises ethical concern because their isolation requires the disruption of the blastocyst. Unsuspected properties of tissue stem cells to transdifferentiate towards a wide variety of different tissues have led to renewed interest in very primitive neonatal/fetal blood, which is a source of stem cells that may be more capable of producing high numbers of specialised cells for cell replacement therapies. In this paper, we review recent advances in the manipulation, banking, characterisation, differentiative potential and clinical use of neonatal/fetal stem cells.