This study sought to examine the sort, frequency, and sources of writing wrongs committed by adult Iranian EFL students. To score the participants’ written essays and speaking interviews, the four criteria specified for the IELTS Speaking and Writing Band Scores (British Council, 2014) were taken into consideration. The study also tried to comparatively analyze the error categories made by men and women learners regarding the type and frequency of their linguistic errors. To gather the information, from the population of faculty members at Hormozgan University of Medical Sciences (HUMS) in Bandarabbas, Iran, 100 adults, both male and female, with their age ranging from 31 to 52, were selected using convenient sampling. Based on their previous IELTS band scores ranging from 4 to 6, the members are separated into three groups.

The results of data analysis revealed that verb tense was the very common grammatical mistake done by members in all three groups. For the cohesion and coherence and lexical sub-categories, relative clauses and incorrect use of target lexical item were regarded as the most common categories of errors. Outcomes of Chi-Square analyses also showed substantial differences among errors committed by participants in different groups. Finally, the comparison between male and female participants’ errors revealed that male participants made both written and spoken errors more than females. According to the results, recommendations, and any suggestions that are of importance to teachers and policymakers as well as to EFL learners are presented in detail.