High cost conducting metals such as Au or Pt are generally used as counter electrodes in quantum dot sensitized solar cells. In this article, we report working of a CdS quantum dot sensitized ZnO thin film solar cell, having FTO as working electrode and aluminium as counter electrode. The CdS quantum dots are prepared by simple low cost chemical technique and characterized by absorption spectroscopy, X-ray diffraction, atomic force microscopy and high resolution trans electron microscopy. These quantum dots are used as an active layer in a solar cell and current density–voltage characteristic of the solar cell is obtained under white light illumination and dark conditions.