The study is devoted to the evaluation of the determinants of job-education mismatches and their impact on salaries of university graduates. We use a comprehensive and nationally representative survey of Russian university graduates. The study employs a self-evaluated measure of mismatch and a statistical variant for robustness and interpretation purposes. We find that one-third of the graduates in Russia are horizontally mismatched, and that the share of mismatched graduates in Russia is higher than the average in OECD countries. Graduates from fields that generate more general human capital, or where low pay is common, are more likely to be mismatched. On the contrary, graduates in Medicine, which is a more specialised field, are more likely to be matched. We find that mismatches negatively affect the earnings of university graduates and, the higher is the degree of mismatch, the higher is the penalty for the mismatch. The study depicts that mismatch is penalised in the majority of fields except for low-paid ones.