Tarlov or perineural cysts are lesions of the nerve root most often found in the sacral region. Several authors recommend surgical treatment of symptomatic Tarlov cysts. However, successful surgical treatment is dependent on appropriate patient selection. In this article, we report three cases of a sacral perineural cyst, causing sciatic pain, and emphasize the usefulness of CT-guided percutaneous aspiration as an important diagnostic and prognostic procedure prior to definitive operative treatment.