Determining students' language proficiency is essential for successful instruction and learning objectives in many educational settings. To this end, one of the most efficient assessment tools for measuring language proficiency is the C-test. Thus, the primary aim of this research is to assess the performance of university students through the C-Test and to analyze the extent to which this test is valid in measuring language ability. A standardized C-Test has been created with four brief passages, each containing 20 gaps. The length of each passage varied from 95 to 109 words. Throughout each passage, only the first and last sentences were not changed. The test was taken by 100 students; 39 were male and 61 were female at Al-Nisour University/Department of English in Baghdad, Iraq. The sample consists of two groups. Both groups come from the same school and would receive similar educational input in both cases based on their grade level. The validity and reliability of the C-Test were investigated using various techniques. The study analyzed the performance of fourth- and third-year students on the Common Language Proficiency Test in Iraq. The results showed that the test discriminates well between high-ability and low-ability examinees, with no significant difference between the two groups. The Rasch model separation reliability was relatively high, and the data were one-dimensional. The students faced difficulties in guessing the most appropriate words due to their limited English proficiency. The results suggest that developing and implementing this test could significantly improve students' academic achievements in basic foreign language classes in Iraq.