A diastereoselective Mannich reaction of simple α-fluoro ketones with N-tert-butylsulfinylimines was developed. This method provides a concise route to a variety of structurally diverse α-fluoro-β-amino ketones containing fluorinated stereogenic carbon centers; good yields and high diastereoselectivities were achieved. This method uses readily accessible starting materials and has a broad substrate scope: cyclic and linear α-fluoro ketones and fluoromethyl ketones are all suitable substrates.