Multifunctional biomimetic nanogels based on zwitterionic poly(carboxybetaine methacrylate) (pCBMA) were synthesized by inverse microemulsion free-radical polymerization. pCBMA nanogels exhibited excellent stability in 100% fetal bovine serum. Dextran labeled with fluorescein isothiocyanate (FITC-dextran) was encapsulated in nanogels as a model drug. Encapsulated FITC-dextran exhibited controlled release from the pCBMA nanogel. Additionally, pCBMA nanogels carry abundant carboxylate groups as functional groups used to conjugate ligands to the nanogels for targeted drug delivery. Flow cytometry results obtained showed that pCBMA nanogels conjugated with cyclo[Arg-Gly-Asp-D-Tyr-Lys] ligands dramatically improved the nanogel uptake by primary human umbilical vein endothelium cells. Functionalizable zwitterionic pCBMA nanogels hold great potential as targeted drug-delivery vectors for biomedical applications.