This study undertook a detailed analysis of the representation of lexical cohesion within the research background sections of undergraduate theses at an Indonesian university. Utilizing a quantitative approach, the research aimed to investigate the frequency and percentage distribution of lexical cohesion devices employed by students in their writing. The primary data collection tool was note-taking, with data drawn from a selection of undergraduate theses submitted by students of English Language Education. The study revealed that repetition was the predominant lexical cohesion strategy, accounting for 93% of instances. It was followed by lesser-used strategies, such as synonym use (4%), collocation (2%), and superordinate terms (1%). However, the research has its limitations; the findings were specific to one group of students within a single university context and based solely on theses, thus potentially lacking wider applicability. The implications of the study highlight the necessity to increase students' awareness and application of diverse lexical cohesion devices. While repetition was a primary strategy, the sparse use of synonyms, collocations, and superordinates indicates areas for enhanced teaching and practice in academic writing. By encouraging a more varied use of these strategies, we can promote improved coherence, richness, and sophistication in student academic writing. This research underscores the importance of diversifying cohesive devices to enrich students' academic writing skills.