The purpose of this research was to conduct case studies to explore and describe Thai university students' awareness and application of cognitive and metacognitive strategies when reading and writing in English-as-a-foreign-language (EFL). Four participants, including two high and two low English language proficiency learners, were selected from 14 students enrolled in a five-week course called English for Social Sciences offered at Kasetsart University in Bangkok, Thailand in 2005. The major sources of data for the analyses included the transcripts of the participants' pair discussions, think-aloud protocols, interviews, and daily journal entries. In addition, field work observations, reading and writing strategy checklists, participants' written work, and the comparison of the pretest and posttest results were also instrumental to the analyses. The interpretive approach of content analysis was employed for these four case studies. Findings were initially derived from the single-case analyses, and then from cross-case analyses. Major findings revealed that strategic knowledge enhanced these English-as-a-foreign- language (EFL) learners' proficiency in English reading and writing. However, applying elaborative strategies for higher-level reading was challenging for most of the participants. Two crucial factors that impeded their development were the learners' uncertain procedural and conditional knowledge of strategy uses and their limited English language proficiency due to limited exposure to the second language (L2). The teacher's explanations and modeling of strategies, the participants' opportunities to discuss strategy use with peers, and extensive practice positively enhanced their development. Additionally, the learners' schema and knowledge of text structures played significant roles in their development of the two skills. These English-as-a-foreign-language (EFL) learners also developed metacognitive awareness and strategy applications, but not to the level that always enhanced effective regulation and control of their reading and writing behaviors. Combining reading and writing in English-as-a-foreign-language (EFL) instruction promoted the learners' awareness of the relationships of certain strategies for the two skills, and developed their literacy skills holistically.