To study chromosome analysis by comparative genomic hybridization (CGH) compared with the conventional technique in early amniocentesis.Cross-sectional descriptive study design was performed in 32 singleton pregnant women with gestational age between 12-15 weeks. Transabdominal amniocentesis was carried out under ultrasound guidance. The amniotic fluid samples were simultaneously investigated using CGH and the conventional cytogenetics study as a gold standard.Amniocentesis were done for advanced maternal age in all cases. The mean maternal age was 35.8 years (35-42 years). The mean gestational age was 13.7 weeks (12-15 weeks). The chromosome analysis by CGH technique of uncultured amniocyte showed 17 normal female chromosomes (53.1%) and 15 normal male chromosomes (46.9%). This finding was the same as the conventional cytogenetics method. The mean duration of the CGH method was 6 days and that of the conventional cytogenetics method was 13.7 days (10-23 days).The CGH technique is a reliable technique for a rapid prenatal diagnosis of chromosome study in early gestation.