We present an accurate computation of the g-factors of the hyperfine states of the hydrogen molecular ion H2+. The results are in good agreement with previous experiments, and can be tested further by rf spectroscopy. Their implication for high-preci
sion two-photon vibrational spectroscopy of H2+ is also discussed. It is found that the most intense hyperfine components of two-photon lines benefit from a very small Zeeman splitting.
