Finger-sucking habit, or nonnutritive sucking, usually ceases spontaneously in childhood. If the habit is not broken, however, not only will dental occlusion be affected, but the shape of the finger may be altered as well. When the habit is broken, the threatening disturbances of digital growth and dental occlusion will resolve spontaneously. This article describes a unique type of habit-breaking appliance applied on the sucked fingers of 2 children with mental retardation. The advantages of this type of extraoral appliance are discussed. Keywords: acrylic appliance, finger-sucking habit, habit breaker, mentally retarded children