Due to the unquestionable roles of technology in language classes, it might be necessary to use computers in assessing language knowledge. This study aimed to examine how computers may be used to assess language ability of [English for Specific Purposes] ESP students. Sixty computer-major university students at Abadan University are the participants of this study. They have taken an ESP course for a four-month academic term. To measure these participants' ESP knowledge, two types of tests were used: a final achievement test based on course content, and a computer-assisted test based on [target language use] TLU domain. The study used a computer-assisted test to highlight the validity of the final achievement test. This study also investigated ESP students' perception of computer-supported assessment and highlighted some obstacles that may hinder e-supported activities in an Iranian context. Regarding the findings, the study points to the possibility of using computer-assisted assessment as an alternative to the present a mainstream testing system.