Post-hatch brood amalgamation is common in many waterfowl species and especially prevalent in the Common Eider (Somateria mollissima). Studies in the temperate region have shown that brood abandonment is influenced both by female body condition and brood size. In this study we tested how these two factors influenced the probability of brood desertion in eiders breeding under harsh conditions in the high Arctic (78N). We found that females in poor body condition were less likely to care for their young, but there was no effects of brood size. We speculate that the differences between southern and northern populations of eiders may be due to different environmental conditions.