AbstractTransferrin and mouse anti‐human CD71 monoclonal antibody were respectively conjugated covalently to the core/shell CdSe/ZnS quantum dots with 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride and N‐hydrocylsulfo‐succinimide (Sulfo‐NHS). The conjugation worked well and the bioactivities of these macromolecules still remained, which was verified by column filtration, sodium dodecyl sulfate polyacrylamide gel electrophoresis, absorption spectra, fluorescence spectra, and circular dichroism spectrometry. Thus, these two kinds of quantum dot conjugates were used to recognize the tumor cells involved. In case of pseudo positivity, FITC‐labeling secondary antibody IgG was used, and the results showed that as‐prepared fluorescent quantum dot bioprobes were highly specific to tumor cells. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007