CdHgTe nanoparticles (NPs) with the emission in the near-infrared regions were prepared in aqueous solution, and were characterized by transmission electron microscopy, X-ray diffraction spectrometry, spectrofluorometry and ultraviolet-visible spectrometry. Based on the fluorescence quenching of CdHgTe NPs in the presence of proteins, a novel method for the determination of proteins with CdHgTe NPs as a near-infrared fluorescence probe was developed. Maximum fluorescence quenching was observed with the excitation and emission wavelengths of 500 and 693 nm, respectively. Under the optimal conditions, the calibration graphs were linear in the range of 0.04 x 10(-6)-5.6 x 10(-6) g ml(-1) for lysozyme (Lyz) and 0.06 x 10(-6)-6.1 x 10(-6) g ml(-1) for bovine hemoglobin (BHb), respectively. The limits of detection were 13 ng ml(-1) for Lyz and 27 ng ml(-1) for BHb, respectively. Four synthetic samples were determined and the results were satisfied.