The palmo-mental reflex (PMR) is a neurological sign found in normal children under the age of 3 years, but disappearing with age. A study population consisting of 45 children with cerebral palsy (CP) and control populations of 136 children with attention deficit disorder/learning disabilities (ADD/LD) and 33 children with idiopathic epilepsy were examined for the presence or absence of the PMR and for the prominence of the reflex (on a 0 to 16 point scale) within three developmental periods (3-8 years; 8 to 13 years, and 13 years and over). Findings indicated that 87% of the children with CP demonstrated the PMR, in contrast to 32% of children with AD/LD and 36% of children with idiopathic epilepsy. The PMR was found to be more intense as well as more persistent among children with CP. The findings are consistent with existence of other primitive reflexes in cerebral palsy that under normal circumstances would be expected to disappear with age. The marked persistence of PMR in cerebral palsy can be viewed as an indicator of pyramidal and/or extrapyramidal tract injury resulting in the dishinbition of “primitive” subcortical and brain-stem centers.