In this paper, an attempt has been made to study an FMEA technique in manafacturing processes of two companies in Vietnam: a can manafacturing process of Anh Binh Minh Company and a process testing chip set of Intel Product Vietnam Ltd. The parametters of traditional FMEA have been analysized in this study: S (Serverity value), O (Occurrence number), D (Detection number), RPN (Risk Priority Number). A new point of this study is to use modified FMEA, it is RAV (Risk Assessment Value). The study has determined the failure modes systematically and comprehensively. The failure modes have been prioritized for improvement and the solusions have been suggested respectively. After the pilot implementation of the solusions, the failure modes have reduced considerably. The paper has also drawn some experiences in implementing FMEA in Vietnamese companies.