This study compares and contrasts lexical cohesion in English and Persian abstracts of Iranian medical students’ theses to appreciate textualization processes in the two languages. For this purpose, one hundred English and Persian abstracts were selected randomly and analyzed based on Seddigh and Yarmohamadi’s (1996) lexical cohesion framework, a version of Halliday and Hasan’s (1976) and Halliday’s (1985) taxonomies. For contrastive analysis, the SPSS package was used. The results revealed some similarities and differences in the use of lexical cohesion sub-categories in the parallel English and Persian texts. The occurrence of all sub-types is nearly the same in the two groups of texts and the two- tailed t-test employed showed that the differences are not statistically significant. Both languages exhibit a general tendency in using repetition, but synonymy and meronymy are the least used sub-categories. Regarding the density of the texts, the analysis indicates that Persian abstracts are denser than their corresponding English ones.