Depending on a child's age, there are different signs that may suggest the presence of cerebral palsy. A newborn infant with difficulty in suckling, evacuating the bowels, or breathing should be carefully evaluated, as these are all warning signs of cerebral palsy. Infants may also have abnormal reflexes. As an infant grows, consistent use of one part of the body over the other, or consistently favoring certain postures over others, may also be signs of cerebral palsy. An infant with cerebral palsy may be unusually floppy or stiff, or retain certain reflexes that are normally present at birth but typically disappear as a baby grows. Lack of facial expressions, not following movements with the eyes, not following sounds with head movements, and lack of a response to human voices also suggests something may be wrong. Infants and children with cerebral palsy may be unable to roll over, crawl, sit up, smile or walk or only be able to do so with help. Grasping or playing with toys may be impossible.

Other signs of cerebral palsy depend on the type of cerebral palsy a patient has. Spastic diplegics have legs that may cross at the knees and a typical 'scissors' gait. Patients with spastic hemiparesis have uncontrollable tremors in one half of the body. If athetoid cerebral palsy is present, slow writhing movements of the extremities, face or tongue may be present along with grimacing and drooling. Ataxic cerebral palsy patients have an unsteady, wide-based gait, difficulty performing fine motor tasks like buttoning a shirt, and intention tremors that occur while performing voluntary movements.

Because cerebral palsy can be difficult to diagnose, any sign of developmental delays, abnormal movements or abnormal posture in an infant or small child should immediately be brought to the attention of a physician.