Thioglycolic acid (TGA)-capped CdTe nanoparticles (NPs) were synthesized in aqueous medium, and their application as fluorescence probes in the detection of adenine and guanine was studied. The TGA-capped CdTe NPs were characterized by transmission electron microscopy, X-ray diffraction spectrometry, spectrofluorometry, Fourier transform infrared, and ultraviolet-visible spectrometry. Based on the significant enhancement of fluorescence emission of these CdTe fluorescence probes in the presence of adenine or guanine, a quantitative analysis method for these purines was proposed. Experimental conditions that govern the extent of fluorescence enhancement were optimized. Under the optimal conditions, the relative fluorescence intensity versus adenine or guanine concentrations gave a linear response, permitting the dynamic range of 7.0 × 10 -7 -1.0 × 10 -4 mol/L and 6.0 × 10 -7 -9.0 × 10 -5 mol/L for adenine and guanine, respectively. The method has also been applied successfully to the detection of adenine and guanine in synthetic samples with satisfactory results.