Symptomatic sacral perineural cysts are uncommon. Several hypotheses have been proposed to explain the etiologies of perineural cysts, but the accurate etiologies remain unclear. We experienced two cases of symptomatic sacral perineural cysts (Tarlov cysts) in one family, who presented with perianal paresthesia. Both of them were operated and postoperatively their symptoms were disappeared immediately. We experienced the excellent treatment outcome with the surgical management of symptomatic perineural cysts in the sacral region. We assume that the theory of congenital origin including a familial tendency is the most plausible of the hypotheses that have been proposed.