A series of highly crosslinked microgels has been prepared at room temperature via photoinitiated polymerisation in dilute solution using methyl methacrylate (MMA) and ethylene dimethacrylate (EDMA), respectively as non-functional monomer and crosslinker in N,N-dimethylformamide (DMF) as a solvent. The effect of monomer concentration and EDMA/MMA ratio on the yield, molecular weight and microgel size was studied and the data were compared to those previously obtained for microgels of similar composition prepared by thermal initiation. This mild polymerisation method yields better results compared to the more conventional thermal method, since it allows higher monomer concentrations to be employed as well as a better microgel size control. Consequently, the method can be advantageously used for the preparation of highly crosslinked microgels with improved properties, particularly useful, e.g. for molecular imprinting applications.