Highly oxygenated organic molecules have been suggested to form a large part of secondary organic aerosol. However, with their exotic structures, their volatilities are not well known, making their exact role in particle formation hard to assess. In laboratory experiments, we found the volatility of HOMs formed in the ozonolysis of the monoterpene alpha-pinene to be in the middle of earlier estimates. The volatilities of HOMs could be well explained in terms of their molecular formulae.