We report here the derivation of two new human embryonic stem cell lines, Man-1 and Man-2, and their full characterization as novel pluripotent stem cell lines. Man-1 was derived from an embryo surplus to requirement from routine IVF, while Man-2 was obtained from an oocyte classified as failed to fertilise and subsequently chemically activated. We report the characterisation of pluripotency and the differentiation potential of these lines. Work is in progress to establish novel methods of stem cell derivation and culture, which will avoid the use of xenobiotics and be relevant to clinical production of human embryonic stem cell lines. Both newly derived human embryonic stem cell lines will be available for the research community from the UK Stem Cell Bank (http://www.ukstemcellbank.org.uk).