AbstractPorotic hyperostosis (PH) is a well‐recognised skeletal indicator of physiological stress occurring during the early years of childhood growth. Although frequently found starting from the Neolithic, PH is poorly documented among earlier Palaeolithic hunter–gatherers. This study reports a case of PH in a Late Upper Palaeolithic skeleton (Villabruna 1) from northern Italy. Macroscopic and radiographic examinations of the skeleton show symmetric porotic lesions of the cranial vault, hair‐on‐end appearance, thinning of the cortical bone, diploic expansion and very slight cribra orbitalia (CO). All lesions are highly remodelled and suggest a condition suffered long before death. A differential diagnosis, carried out in order to discriminate between infectious and acquired conditions, points to anaemia as likely aetiology for the changes observed. Absence of postcranial involvement, lesion healing and survival to adulthood suggest a diagnosis of acquired anaemia. Among acquired anaemias, both dietary and infectious models are discussed in light of the individual's skeletal characteristics, as well as geographic location, paleoenvironmental data, subsistence modality and dietary information. The combined analysis of these data suggests that parasitic infestation resulted in megaloblastic anaemia in this individual. Copyright © 2009 John Wiley & Sons, Ltd.