Objective: Amniocentesis is the most common test used for prenatal diagnosis of a chromosome problem in the fetus. It involves the removing a small amount of amniotic fluid which surrounds the fetus in the amniotic sac. The amniocentesis sample is sent to the laboratory where the cells are cultured and then the chromosomes are analyzed. A new supplemented medium has been developed to improve amniotic fluid cell growth in mouse. Materials and Methods: The medium consists of a mixture of Ham's F12 medium and Dulbecco's modified Eagle's medium (DMEM) supplemented with antibiotics and 20% fetal calf serum (FCS). Results: Good clonal growth is achieved consistently in 4-6 days without any mycoplasma contamination. The volume of amniotic fluid required to initiate culture can be as little as 1 ml. Amniotic fluid samples contaminated with red blood cells with no visible clot also grow well. Conclusion: The results of amniocentesis will indicate the likelihood of the fetus developing certain chromosomal conditions such as Down's syndrome Edward's syndrome and Patau's syndrome which are all conditions where the fetus is born with an extra chromosome.