The authors present two cases of a very rare condition known as familial paroxysmal choreoathetosis. The patients, mother and daughter, were 28 and 8 years old and the disease started when they were 6 and 2 year-old, respectively. The paroxystic involuntary movements were generalized, producing speech and gait disturbances, without any impairment of consciousness. The duration of the episodes lasted 30 to 180 minutes. The paroxysmals occasionaly could be triggered by physical stress or alcohol intake. The neurological examination and the electroencephalogram during free intervals were normal. Searching the available literature these twq cases could be classified as belonging to the same form described by Mount and Reback, in 1940.