Abstract: Molecular imprinting, an established technique for the synthesis of insoluble crosslinked polymers with specific cavities for selective molecular recognition and catalysis, has been applied to highly crosslinked polymer nanoparticles (microgels) able to build stable solutions in appropriate solvents. Imprinted microgels with a nominal crosslinking degree above 50 wt.-% could be prepared by solution polymerization in high dilution. They were characterized by GPC, viscometry and membrane osmometry, and were found to be highly crosslinked macromolecules with a molecular weight comparable to the one of proteins. Molecular recognition experiments clearly pointed out the presence of functionalized cavities within the microgels that were able to recognize and to selectively bind sugar molecules. The experiment can be carried out in homogeneous solution, after which the microgels are conveniently separated by ultracentrifugation. Although the obtained selectivities are still low compared to the results achieved with insoluble crosslinked polymers, the success of this approach represents an important step towards the development of what might be properly described as "artificial enzymes"