This study examined EFL learners' attitudes and motivation towards learning English through content-based instruction (CBI) at a university in Thailand. Seventy-one (71) university students, the majority sophomores, answered a 6-point Likert scale questionnaire on attitudes and motivation together with six open-ended questions regarding learning the CBI-based course. Classroom observations were conducted and the scores of mid-term and final tests were collected. Statistical analysis showed that in general the students held a considerably positive attitude towards the CBI-based course and their motivation for learning English was at a moderate level. Significant differences were found in attitudes between students from the Faculty of Nursing and those from the Faculty of Medicine while motivation between the students from these two programs was not significantly different. It is recommended that teachers of CBI-based courses should adopt motivational strategies to enhance both the students' instrumental motivation and integrative motivation, and further studies should investigate learning environment, learner identity and learner engagement in the CBI classroom.