Consideration of the mortality distributions of 206 European and Near Eastern Neanderthals (40 associated skeletons and 166 isolated elements), compared to those of 11 Recent human ethnographic and palaeodemographic samples and two non-human mammalian samples. indicate that there is a clear representational bias in the total sample, with too few infants and older adults plus too many adolescents and prime-age adults. Manipulations of the Neanderthal data produce immature mortality distributions within the ranges of the Recent human samples, but they maintain the high prime-age adult and low older adult mortality. This high young adult mortality in the Neanderthal sample does not appear to be a product of differential preservation or recognition of fossil remains or the systematic underageing of older adults. However. it is likely to be the product of a combination of demographic stress (associated with high levels of stress indicators), the effects of pooling across temporally and geographically diverse and fluctuating Neanderthal populations, the need for full mobility among all individuals and hence a dearth of older individuals dying in shelters, and (possibly) differential disposal of older individuals in shelters. The first three factors support the interpretations of high levels of adaptive stress previously suggested by palaeopathological analyses of their remains.