Fourteen dogs with clinical signs compatible with a spinal arachnoid cyst were presented and examined at the Department of Medicine and Clinical Biology of Small Animals (Ghent University) between November 2000 and September 2004. The typical presentation was a slowly progressive non-painful ataxia. The diagnosis of a spinal arachnoid cyst was made by myelography, in some cases followed by computed tomography. Six dogs were treated surgically. Three dogs underwent durectomy and three dogs durotomy. All dogs were available for short-term follow-up and five out of six dogs were available for long-term follow-up (more than 1 year post surgery). Both the short-term and long-term results were promising.