This paper presents a statistical Word Sense Disambiguation with application in Portuguese-Chinese Machine Translation systems. Due to the limited availability of Portuguese-Chinese resources in the form of digital corpora and annotated Treebank, an unsupervised learning and a non-aligned bilingual corpus are applied. The proposed method first identifies words related to each of the ambiguous words based on their surrounding words and relative distance. A mathematical model is then applied in the identification of the most suitable sense of an ambiguous word in terms of the related words. All the senses discovered are converted into a set of rules and stored in the Sense Knowledge base for later use in disambiguation and translation process. Preliminary experiment results show an improvement of 6% in assigning correctly the corresponding translation over the baseline method. © 2005 IEEE.