Reading strategy use has long been considered an important factor in the evaluation of effective second language (L2) reading. It is generally believed that proficient and less-proficient readers differ in their reading process and strategy use. The purpose of this study was to examine the reading strategy use of high- and low-proficiency level college students in Taiwan and the reading problems that might arise in their reading process. A General English Proficiency Test (GEPT) and a modified reading strategy questionnaire, based on Carrell (1989), were administered to 45 Taiwanese college students. The results show that language proficiency has a significant effect on strategy choice and use, and high achievers and low achievers are different in the quality and quantity of their reading strategy use. More proficient learners in the study were found to utilize more top-down and context-related strategies, while less-proficient learners tended to focus on bottom-up and lexical-related strategies. Also, limited vocabulary knowledge is the most important reader factor of Taiwanese college students' reading problems. The study concludes with a discussion of implications for L2 reading instruction and learning in the classroom setting.