Optimized laboratory-scale preparation of methyl 3,3,3-trifluoropyruvate ( 3, MTFP) has been developed starting from industrial hexafluoropropene-1,2-oxide ( 1, HFPO) via methyl 2,3,3,3-tetrafluoro-2-methoxypropanoate ( 2, MTPr), which was transformed to 3 using sulfuric acid with isolated yields up to 81%. Byproducts formed in the transformation of 2 to 3, viz. methyl trifluoroacetate ( 4, MTAc), methyl 3,3,3-trifluoropyruvate hydrate ( 5), methyl hemiacetal of trifluoropyruvate ( 6), a dimer of methyl 3,3,3-trifluoropyruvate hydrate ( 7, DimMTP), and methyl fluorosulfate ( 8, Sulf) were identified and their amounts determined under various experimental conditions. Potential reaction pathways leading to the formation of the byproducts are discussed.