Many migratory bird species, particularly those that nest in the Arctic, are experiencing population declines possibly linked to ongoing environmental change in this region. Understanding linkages between climate change, contaminant exposure, and reproductive parameters is thus important to conservation and management of these species. However, the potentially important effects of changes in ambient temperature and contaminant exposure on incubation patterns and offspring characteristics have received little attention in Arctic wildlife. To evaluate the extent to which temperature and contaminant exposure might affect incubation conditions and offspring characteristics in arctic-breeding bird species, we used a shorebird (semipalmated sandpiper; Calidris pusilla) model. We measured ambient temperature, nest temperatures, and POPs levels in eggs and assessed their effects on length of incubation and chick mass at hatch. Our specific questions are (1) to what extent do fluctuating spring ambient temperatures and differences in timing of nesting affect temperatures experienced in the nest; and (2) what are the relative influences of temperature and contaminant levels on incubation duration and mass of chicks at hatch?