The electrochemical fluorination of a variety of N-protected lactams was carried out and Et3N-5HF was found to be superior to Et3N-3HF as the electrolyte. When 5-and 6-membered N-acetyl or ethoxycarbonyl lactams were used as substrates, the fluorination reaction selectively took place at the α-position of the lactam nitrogen and the corresponding monofluoro products could be obtained in good yields.