In this paper we will describe the work that is being cooperatively done by Portugal and Brazil. It uses Statistical Methods for Natural Language Processing. Namely, we will focus on the problem of Part-of-Speech (POS) Tagging. POS Tagging is a recent and successful technique for assigning each word in a sentence its correct POS tag. This technique can achieve more than 96% of accuracy, even with unseen untagged texts. All steps involved in this process will be described as well as the problems faced. Besides, we will present the stochastic approach to POS Tagging, which treats the generation of tag alignments as a probabilistic problem. Finally, we will report the results achieved by using these kinds of techniques for Portuguese texts.