The paper concerns the highly controversial claim made by the Dalai Lama of Tibet in 1996 that Han immigration into the Tibetan areas of China was so extensive as to make up a major part of "cultural genocide". It looks carefully at data concerning Han immigration into the Tibetan area and concludes that although immigration has occurred the Dalai Lama's supporters have vastly exaggerated it; the claim of "cultural genocide" is unsustainable.