Human induced pluripotent stem (iPS) cells derived from somatic cells of patients hold great promise for modelling human diseases. Dermal fibroblasts are frequently used for reprogramming, but require an invasive skin biopsy and a prolonged period of expansion in cell culture prior to use. Here, we report the derivation of iPS cells from multiple human blood sources including peripheral blood mononuclear cells (PBMCs) harvested by routine venipuncture. Peripheral blood-derived human iPS lines are comparable to human embryonic stem (ES) cells with respect to morphology, expression of surface antigens, activation of endogenous pluripotency genes, DNA methylation and differentiation potential. Analysis of Immunoglobulin and T-cell receptor gene rearrangement revealed that some of the PBMC iPS cells were derived from T-cells, documenting derivation of iPS cells from terminally differentiated cell types. Importantly, peripheral blood cells can be isolated with minimal risk to the donor and can be obtained in sufficient numbers to enable reprogramming without the need for prolonged expansion in culture. Reprogramming from blood cells thus represents a fast, safe and efficient way of generating patient-specific iPS cells.