Cojoined twins was analyzed type cephalothoracoabdominopagus, is especially rare case of dysgenetic abnormalities, in which the heads, necs, thoraces and abdomen are joined. Twins births joined have been said to occur with a frequency of 1 per 100,000 deliveries, but the incidence of this malformations is one in three million conjoined twins. Conjoined twinning may be associated with a more fundamental failure of embryonic migration or may be associated with a more fundamental failure of ambryonic migration or fusion, 95% of conjoined twins are females. The Janiceps type of cephalothoracoabdominopagus derives its name from Janus, in Roman nythology, the god of doors and gateways, his statue with two faces, facing east and west for the beginning and ending of the day. The anatomic features with the Janiceps type of cephalothoracoabdominopagus are describe, and the mechanisms that may have played a role in the abnormal development of these twins are discussed. The mother was a 22-year-old, with last menstrual period January 12, 1997. She came to the other medical center, with an ultrasound study performed at 27 weeks' gestation, and possible multiple fetal anormalies, a second ultrasound examination, confirmed abnormalities, two hearts, as well as polihidramnios. Past history included normal espontaneous vaginal delivery of healthy term infant, who were alive and well, family history was negative for congenital anormalies, and no prior history of twinning. She denied use of drugs, alcohol, or cigarettes; had no fever, vaginal bleeding, or other problems with the pregnancy. The abdomen was gravid to 48 cm, and contractions were palpable, fetal heart tones were 1400 beats per minute. On the one day of admission the patient underwent delivery of conjoined infants, the Apgar scores were zero at 1 minute and at 5 minutes. The infants were joined front-to-front, with two faces, each a compositive of toth twins, each twin han four extremities, in each face resambled a one nose, with structure incomplete in one face, esophagi were fused. Each twin had its own skeletal system extending from the cervical spine downwards. The congenital malformations for each conjoined twin are listed in the autopsy report, abnormalities included absent ovary and uterus in both twin. COnjoined twins develop from a single zygote, the cause is unknown. We proposed, embryonic tissue divides incompletely, likely to result in twinning anomalies from the 15th to 16th day postovulation, during the late part of period six, about the third week.