The purposes of this research were to: 1) study the students' reading problems in terms of reading strategies prior to the implementation of the supplementary exercises, and 2) compare the students' learning achievement in terms of reading skills and strategies before and after implementing the supplementary exercises. The research sample, selected through a purposive sampling technique, comprised 275 third-year students enrolled in the Faculty of Humanities and Social Sciences at Thepsatri Rajabhat University and failed in Reading Exit Exam in the 2nd semester of 2016 Academic Year. The instruments of the study consisted of pre-and post-tests, Reading skills and strategies supplementary exercises, and structured interview. The quantitative data were analysed by means, standard deviation, percentage, and t-test whereas the content analysis was conducted to analyse the qualitative data. The study revealed that the students' reading problems were classified into two main issues: the confusion of using each reading strategy and less frequency usage. The comparison of the results before and after implementing the reading supplementary exercises showed statistically significant differences at the .01 level. Most of the students obtained better results after learning through the supplementary exercises and could employ each reading strategy with more confidence when retaking the examination.