We report the case of a baby with transient generalized stiffness noticeable from the first days of life, hyperreflexia, massive jerks in response to sudden tactile and acoustic stimuli, and long-lasting myoclonic jerks closely resembling epileptic seizures. The father and paternal grandfather both had hyperekplexia. At age 3 years, the child had normal psychomotor development and persistent abnormal startle response to unexpected sounds or touch.