Problem-based Learning (PBL) is an influential and innovative method in language learning, where the real-life situations and issues of the learners are used as 'problem situations' in developing many other skills. Despite Sri Lanka marks a high literacy rate in Asia, it lies behind the average values of IQ abilities. Even though the country offers free education, it is observed that the competitive education system doesn't encourage its learners to develop their cognitive abilities and other soft skills. This research was aimed to find out the effectiveness of PBL in enhancing logical and analytical thinking skills. Its objectives were to study the influence of PBL in language education and to find out if logical and analytical thinking abilities be enhanced through PBL. The hypothesis was logical and analytical thinking abilities of the undergraduates can be developed through PBL. The research got a mixed-method approach. The target population consisted of 60 randomly selected undergraduates of a Sri Lankan University. A special module prepared by the researcher, based on developing cognitive skills of the undergraduates was tested on the population. A pre and a post 'spot-test' on critical thinking was given and the answers were individually compared and analyzed to see the impact. Randomly selected ¼ of the target group was interviewed to get the student perspective of PBL. It was noted that the thinking patterns of the students have developed; proving the capacity of PBL in developing thinking patterns in a positive way. It was confirmed that not only the analytical and logical thinking abilities, but also other cognitive skills such as critical thinking, justification skills as well as language skills could be developed through PBL.