Owing to the risk of insertional mutagenesis, viral transduction has been increasingly replaced by nonviral methods to generate induced pluripotent stem cells (iPSCs). We report the use of 'minicircle' DNA, a vector type that is free of bacterial DNA and capable of high expression in cells, for this purpose. Here we use a single minicircle vector to generate transgene-free iPSCs from adult human adipose stem cells.