20 cases of paroxysmal kinesigenic choreoathetosis were reported. In this series, 90% cases were sporadic and the male predominated with a sex ratio of 5.7:1. The mean age of onset was 15 years old. The striking feature was the frequent brief tonic, dystonic or choreoathetoid attacks that were triggered by sudden movement, lasting no longer than 3 minutes. The paroxysms reached their climax during puberty with a frequency as much as 30-100 times per day. Spontaneous remissions came about at the age of 20 or so and the paroxysms seldom occurred after 30 years old. The attacks responded to Dilantin and L-dopa. In this series, not only were the attacks triggered by sudden initiation of movements followed a period of inactivity, but also triggered by sudden increase in speed, amplitude, force strength and a sudden addition of new actions during steady movements were in progress. It first called attention to the effect of alcohol on the attacks of the disease. It furnished PKC with a circumstantial evidence of a functional disorder of basal ganglia.