AgInS 2 nanocrystals have attracted intense attention due to their promising applications in printable solar cells, light-emitting diode (LED), and biological labeling. Although much effort has been made to develop various synthesis methods to prepare AgInS 2 nanocrystals, it remains a goal to obtain high quality AgInS 2 nanocrystals. In this work, Zn-doped AgInS 2 nanocrystals were synthesized by diffusing Zn into the preformed AgInS 2 seeds at high temperature in solution. The resulting Zn-doped AgInS 2 nanocrystals had welldefined spherical morphology with narrow size distribution. By varying the reaction temperature, the emission wavelengths of the obtained Zn-doped AgInS 2 nanocrystals could be adjusted from 520 to 680 nm. The quantum yield of the obtained alloyed nanocrystals could reach 41%, which was reasonably good as compared to those of the previously reported. The obtained Zn-doped AgInS 2 nanocrystals showed promising applications in cell labeling.