Arnold Chiari malformation is one of the commonest cause of congenital hydrocephalus. Cause of fetal development of cerebellar tonsils remains unknown and may be diagnosed at later in life. The association of Arnold Chiari malformation with acromesomelic dwarfism is not known. We report male infant diagnosed with acromesomelic dwarfism at end of gestation period on basis of antenatal ultrasonography findings. An ultrasound scan of infant head at fifth month of birth was performed in view of increasing head circumference that revealed aqueductal stenosis with dilated posterior horn of lateral ventricles in brain.