Supplier quality evaluation is a multi-criteria decision-making (mcdm) problem that involves multiple, heterogeneous criteria of different weights. the literature addresses quality, delivery, technology, value and service as the five most common criteria used for supplier quality evaluation. in this thesis, we have presents a comparative evaluation of supplier selection processes in corporate environments using a case study approach and the iso 9000/ts16949 standards. the corporate environments examined were an automotive, agricultural equipment organization. considering the most important criteria for evaluating the quality of suppliers based on a review of the literature and observation in practice. they include both qualitative and quantitative criteria to reflect the real attributes of the supplier in question, and are applied in a supplier quality evaluation performed for a large data set. finally, these organizations continuously review and implement effective quality systems following the rigorous iso 9000/ts16949 series of standards and most companies have developed in house procedures and software for the supplier selection process. the case study method emphasizes in-depth qualitative analysis and provided an opportunity to explore issues of interest in greater detail and identify particular supplier selection processes. we propose a model for supplier quality evaluation and selection, we address the large size of suppliers’ datasets and present a technique to evaluate the suppliers at supplier-wise, plant-wise, part-wise and process-wise using part per million equivalent. this thesis discusses the increasing importance of suppliers quality cost, particularly in supporting product and service quality, and presents a set of questions that executive managers must ask concerning how well their purchasing and sourcing processes contribute to total supplier quality cost. using supplier quality cost, ranking of supplier was done by calculating qcpi index. this thesis briefly outlines the best practices like ppm agreement to establish a minimum standard for the supplied quality and to encourage suppliers to develop ways of working towards the prevention of non-conformances and their underlying causes implemented by such manufacturers in supplier quality management. this thesis presents an application of six sigma methodology to reduce supplier quality cost in manufacturing industry. although there is a wider acceptance of six sigma in many organizations today, there is still a lack of in-depth case study of six sigma. for the presented work the case study methodology was used. the company decided to reduce quality cost and improve selected process using six sigma methodologies which is beneficial for individual manufacturing organization and also for the practioners. this thesis discusses the quality and productivity improvement in a supplier enterprise through a case study which deals with an application of six sigma dmaic (define–measure-analyze-improve-control) methodology in an industry which provides a framework to identify, quantify and eliminate sources of variation in an operational process in question, to optimize the operation variables, improve and sustain performance viz. process yield with well-executed control plans. six sigma improves the process performance (process yield) of the critical operational process, leading to better utilization of resources, decreases variations & maintains consistent quality of the process output. the main advantage is its ability to deal efficiently with the challenge of evaluating large numbers of suppliers and the data pertaining to their attributes. also a software is design in visual basic which shows result of different supplier like monthly rejection rate, criticality of part in manufacturing through part-wise ppmeq, supplier process-wise ppmeq, ranking of the supplier by calculating quality cost performance index which help organization to track the record of large set of suppliers.