Abstract. X-ray polarimetry is an unexplored area in high energy astrophysics. We describe a Thomson X-ray polarimeter developed for a small satellite mission. The instrument works in the 5-30 keV energy band and will be suitable for X-ray polarization measurement in about 50 hard X-ray sources. Currently, a laboratory model has been made and tested successfully and the design and fabrication of an engineering model is in progress. Different aspects related to mission specifications, instrument design, test results, and sensitivity for polarization measurement are discussed.