We report three cases of herpes zoster sciatica with motor loss preceding the typical skin lesions. Serological tests and cerebrospinal fluid examination established the diagnosis. Two patients had residual motor loss after 1 and 3 months, respectively. Immunodepression and other risk factors should be looked for routinely. Early diagnosis and treatment may improve the prognosis. Tests for antibodies or viral DNA in cerebrospinal fluid can be helpful, although negative results do not rule out the diagnosis.