Considering the pivotal role of assessment, this study aimed to investigate the attitudes of the students and the teachers towards the assessment component of a customized content and language integrated learning in an English as a foreign language program implemented at the tertiary level in Turkey. It also sought to study its effectiveness as a tool for the integrated assessment of language and content. Data were obtained by a mixed-method research approach from 525 university freshman students and 17 English language teachers via questionnaires and follow-up interviews with the teachers and the students. The results indicated that both the students and the teachers developed positive attitudes towards the assessment component of content and language integrated learning. The assessment component was also found to be an adequate tool for the integrated assessment of content and language.