Two-phase cross flows have received minor consideration in thermal-hydraulics research, notwithstanding their applications in chemical engineering systems. Many types of heat exchangers and steam generators have, at least in a segment of the flow path, a cross direction of a two-phase mixture to a tube bank even in nuclear plant components. The departure from nucleate boiling (DNB), or the dry-out threshold, is one of the main limits that characterize the whole flow field. For this reason it has been deemed interesting to investigate the influence of quality on DNB heat flux in flow boiling, employing a 9-tube bundle with cross flow of Freon 12. Rather surprisingly, the DNB heat flux rises with quality. The rise has been tested from the pool boiling DNB value as predicted by Lienhard up to a saturation value 20% higher. The law of increase may be reasonably well predicted following the well-known critical heat flux theory of Zuber.