F1Fo ATP synthase is a molecular rotary motor that is capable of both generating and degrading the energy currency of the cell, ATP. In recent years, cryo-electron microscopy has proved useful in elucidating the molecular mechanism of ATP hydrolysis by F1Fo ATP synthase, but it remains unclear whether the enzyme uses the same principles for ATP synthesis. We have devised strategies to capture F1Fo ATP synthase functioning in synthesis mode with cryo-electron microscopy. This presentation details our steps towards employing those strategies to determine the molecular mechanism by which this rotary motor generates ATP.