In Sigtuna, Sweden, a medieval cemetery, including 227 skeletons, was analysed in 2006. On the outskirts of the churchyard, six skeletons with bone changes indicating systemic inflammatory disease were observed. Two out of three individuals with well-preserved facial bone regions displayed signs of rhinomaxillary remodelling. Four of the afflicted exhibit severe bilateral alterations of the lower legs and phalanges of the feet and concentric atrophy of the metatarsals. In addition, one of the individuals exhibited a kyphosis in the lumbar vertebrae. In a discussion about alternative diagnoses, lepromatous leprosy and tuberculosis were identified as the causes of the destructive lesions in two individuals. Though the skeletal changes of the lower legs and feet in four cases demonstrate a close resemblance to secondary lesions of leprosy, the disease could not be confirmed. The skeletal changes of the last individual were unspecific and the possible causes several, rendering diagnosis difficult. The burial locations imply that the afflicted persons belonged to a lower social stratum. Due to the significantly higher frequency of pathological changes in the cemetery compared to other cemeteries in the town, the individuals could be regarded as fellow sufferers among others with various medical conditions. The bioarchaeological identification of systemic infectious diseases of a group of individuals of this size is unique to Q1 north Q1 of Scania in Sweden, where only a few cases of leprosy and tuberculosis have previously been diagnosed. The significance of the present study is emphasised by the interconnection between the afflicted, the archaeological context and the knowledge of the medieval society in Sigtuna.