This paper reports the development of an integrated vacuum field emission transistor differential amplifier (diff-amp) utilizing nanodiamond emitters. The device was fabricated by a dual-mask self-aligned mold transfer technique using standard silicon microfabrication technique in conjunction with chemical vapor deposited nanodiamond. The emission current of the transistor pair was validated by the Fowler-Nordheim equation. Well-matched field emission transistor characteristics and large common-mode rejection ratio of 55 dB were obtained, suggesting the capability of the device to reject common-mode noises and to amplify the information contained in differential signals.