Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumours of the gastrointestinal tract. Familial GIST with autosomal dominant inheritance and mutation in c-KIT or PDGFR-α, are rare and characterized by multiple GIST, relatively young age at diagnosis and hyperplasia of the interstitial cells of Cajal. Around twenty families with germ line mutations in c-KIT and three families with mutations in PDGFR-α have previously been published. In this case we present a family with familial GIST and mutation in c-KIT.