Understanding the local Seebeck coefficient distribution is helpful for the development of novel thermoelectric materials. Seebeck coefficient distributions of both zone melted and hot pressed samples of I-cloped Bi2Te3 based alloys were measured using microscopic Seebeck coefficient mapping method. Seebeck coefficient differences up to 40-50 muV/K were found between different locations on the same sample. There is no visible relationship between the microscopic Seebeck coefficient distribution and the local surface morphology and element distributions. It is suggested that the local Seebeck coefficient variations were mainly originated from the lattice defects for the zone melted sample and also due to the grain orientation for the hot pressed sample. (C) 2005 Springer Science + Business Media, Inc.