Although the term 'optofluidics' is less than 10 years old, the combination of light and non-solids is being exploited by researchers who are finding applications in fields ranging from imaging, detection of chemical or biological agents and particle control, through to enhancing photonic circuits and energy generation. The October 2011 issue of Nature Photonicshas a special focus on optofluidics dedicated to some of the latest advances in field.