Bob Michell’s research has focused on understanding the biological functions of inositol phospholipids, or phosphoinositides, which are quantitatively minor phospholipid constituents of the membranes of eukaryotic cells. He recognised that receptor stimulation of inositol lipid hydrolysis is a widespread reaction that leads to intracellular mobilisation of Ca²⁺.

His research group identified hydrolysis of phosphatidylinositol 4,5-bisphosphate as the initiating reaction in this process. Later, they discovered a novel phosphoinositide, phosphatidylinositol 3,5-bisphosphate, for which important functions have since been recognised. Bob has also provided insights into the evolutionary origins of the inositol phosphates and phosphoinositides.