Nursing students at King Saud University (KSU) are considered to be low achieving readers. They face difficulties with understanding medical texts due to the fact that they lack some necessary medical vocabulary knowledge. Thus, the researcher used computer-assisted semantic mapping (CASM) with level-three (114 NAJM) nursing students to map medical terms for the purpose of helping such students in vocabulary acquisition. The present study, therefore, aimed at investigating the efficiency of CASM in improving ESP students' vocabulary knowledge.