Motivation and attitude are two affective factors that can determine the success of students' learning. The objective of this study is to investigate how attitude and motivation affect students in bilingual teaching programs. This study comprised a total of 159 Spanish students and was conducted in the third and fourth year of primary education in which the level of the L2 corresponds to A2.1 of the CEFR (Common European Framework of Reference). The study involved two schools in the province of Cordoba (Andalusia) in which CLIL (Content and Language Integrated Learning) program is implemented. A quantitative methodology has been used whereby students' attitude and motivation have been analysed through a questionnaire. The results show that although motivation and attitude are positive in science subjects within the bilingual program, it is necessary to pay greater attention to diversity and to the different pace of learning among students.