Despite progressive disability in sporadic adult-onset ataxia (SAOA), little is known about patients' assessment of their ataxic disorder and its impact on health-related quality of life (Hr-QoL). This study investigated Hr-QoL by means of the following self-administered scales: Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Beck Depression Inventory (BDI), and the Medical Outcome Study Short Form (SF-36). Twenty-two unselected ataxia patients were included. Sleep-related complaints were found in 9 (41%) of 22 and symptoms of depression in 6 (38%) of 16 patients. Compared to a large german control group, SAOA patients had lower scores in all SF-36 dimensions except for bodily pain. The greatest impairment was found in the domain physical functioning, followed by the domains social functioning and role limitations (emotional problems). There was a significant negative correlation of all nonmotor SF-36 dimensions with the BDI score. Walking aid dependency was significantly correlated with poorer health status perception in several motor and nonmotor domains. In addition, impaired sleep quality was correlated with an impaired general health perception and with bodily pain. The study demonstrates a great impact of SAOA on Hr-QoL. Adequate treatment of depression, motor disability, and impaired sleep quality is essential to improve Hr-QoL in ataxic patients.