Abstract Oxygen abundances are derived in a sample of field F and G dwarfs, for which boron abundances have been determined from HST spectra. The metallicities of the program stars span the range of [Fe/H]=−0.75 to +0.15. The weak [O I] λ6300 Å and O I λ6158 Å lines have been used for the oxygen abundance analysis. In addition, the strong near-IR triplet O I lines have been analyzed and these lines tend to give larger O-abundances than those derived from the weak [O I] and O I lines. Using the weak oxygen lines as the primary abundance indicators, a slope of 1.5 ±0.2 is determined for the relation of log ϵ(B) versus log ϵ(O) in the ‘metallicity’ range of log ϵ(O)=8.3–9.0.