Achondrogenesis is a very rare lethal skeletal disorder. Here we describe a case of prenatally diagnosed achondrogenesis typeⅡ in a 28 year-old woman at (17+4) wk. She had history of 5 first trimester missed abortions. The couple is consanguineous. Ultrasonography showed extreme micromelia, short neck and trunk, large head and prominent abdomen. Delayed ossification in sacral bones was detected and ossification of pubic rami was poor. There were associated large cystic hygroma, anasarca and also high occipital cephalocele. Posterior fossa was normal. Mild hypothelorism, depressed nasal bridge, low set ear and mild retrognathia were identified too. Amniocentesis result was compatible with a normal female fetus. Post mortem whole body radiography confirmed the diagnosis. To our knowledge, this is the second case report with association of cephalocele and achondrogenesis typeⅡ.