Cerebellar damage typically results in ataxia and can be caused by stroke, tumor or one of many forms of degenerative disease. Since few pharmacological options are available, most treatments rely heavily on rehabilitation therapy. Little data exist on methods for tracking the progression of ataxia, which is critical for assessing the efficacy of current and newly developing treatments. Here, we tracked the severity of ataxia, with a particular emphasis on gait and balance dysfunction, in a group of individuals with cerebellar damage using the International Cooperative Ataxia Rating Scale (ICARS) and several instrumented laboratory measures of gait and balance impairments over one year. We found that the ICARS was able to distinguish between subjects with static lesions and those with degenerative disorders, was sensitive to increases in ataxia severity occurring over one year, and correlated well with specific instrumented measures of gait in persons with cerebellar degeneration. These results suggest the ICARS is a valuable tool for clinicians and investigators to document and track long-term changes in gait and balance performance in individuals with cerebellar degenerative disorders.