Developmental characteristics of three girls with 18p- syndrome are described, with detailed history and results of psychological and speech/language evaluations completed at various ages. Results suggest that some children with 18p- syndrome have average abilities in selected areas, despite previous reports that these children have mild to severe mental retardation. Two of the three girls had more severe deficits in linguistic, as opposed to nonlinguistic, abilities. All had similar difficulties with speech articulation. It is suggested that children with speech/language delays who have physical features associated with this syndrome have chromosome analysis performed. It is also recommended that children identified as having 18p- syndrome be referred for comprehensive developmental assessments and remedial special education programming before a specific prognosis is determined.