Type 2 diabetes has been a global epidemic for the past two decades, with estimates of 380 million affected by the year 2030. A major factor in this disease is a loss of insulin sensitivity by the insulin receptor (IR), leading to poor regulation of glucose levels. Understanding this loss of sensitivity is therefore important. In this study, we describe, for the first time, a surface plasmon resonance (SPR) technique for measuring the kinetics of interaction between the insulin receptor ectodomain and insulin. The technique uses a scaffold approach, in which an antibody to IR is first bound to the SPR biosensor chip by conventional amine coupling, followed by capture of IR on the antibody and, finally, the measurement of insulin interactions. Each insulin receptor ectodomain has more than one insulin binding site and, as expected, the interaction data from this assay is fitted by a heterogeneous ligand model. A key aspect of the assay is that it uses a multiplex (multiple channel) system that allows replicate, simultaneous measurements of interactions, therefore avoiding problems with ligand degradation during ligand regeneration steps. The advantage of this assay is that it is a rapid, label-free and real-time analysis technique for studying IR-insulin interactions. The assay enables us to explore the subtle differences in the affinities that different insulin receptor isoforms have for insulin and will also enable us to study the possible effects of humoral factors on the IR-insulin interaction.