Purpose: To find the most effective method for extraction of cell-free DNA (cf-DNA) from maternal plasma, we compared a blood DNA extraction system (blood kit) and a viral DNA extraction system (viral kit) for non-invasive first-trimester fetal gender determination. Materials and Methods: A prospective cohort study was conducted with maternal plasma collected from 44 women in the first-trimester of pregnancy. The cf-DNA was extracted from maternal plasma using a blood kit and a viral kit. Quantitative fluorescent-polymerase chain reaction (QF-PCR) was used to detect the SRY gene and AMEL gene. The diagnostic accuracy of the QF-PCR results was determined based on comparison with the final delivery records. Results: A total of 44 women were tested, but the final delivery record was only obtained in 36 cases which included 16 male-bearing and 20 female-bearing pregnancies. For the blood kit and viral kit, the diagnostic accuracies for fetal gender determination were 63.9% (23/36) and 97.2% (35/36), respectively. Conclusion: In non-invasive first-trimester fetal gender determination by QF-PCR, using a viral kit for extraction of cf-DNA may result in a higher diagnostic accuracy.