Calvarial hyperostosis syndrome (CHS) is a rare, non-neoplastic, proliferative bone disease ofthe flat bones of the skull. The lesions of CHS are initially painful, but self-limiting with skeletalmaturity. Therefore, treatment is aimed at relieving pain. Until recently, CHS has only been describedin young Bullmastiffs and the etiology is still unknown. In this report, CHS is describedin a six-months-old, male Weimaraner with the typical presentation of an asymmetrical swellingaffecting the frontal, parietal and sometimes occipital bones of the skull.