This study aimed to identify work-related language competencies required in the manufacturing industry and to provide guidelines for designing English programs that have groups with widely differing language levels and wide-ranging job experience. For this purpose, a questionnaire comprising 65 job-related tasks was used. 2,360 Japanese employees in manufacturing companies were asked to self-rate their abilities to perform the specified tasks in English on a 5-point scale and to indicate whether they had ever performed such tasks before. The data was analyzed according to English proficiency 1) to identify the types of tasks performed at each score level and 2) to examine whether the experience of performing the tasks would affect their self-ratings. Results indicated that the higher the subjects' language proficiency, the more tasks they had performed. Moreover, the subjects with task experience assessed their abilities more highly than those without experience. Further analysis revealed that the tasks requiring productive skills exerted a greater influence on the subjects' self-ratings. Based on the results, a list of tasks was compiled so that educators and trainers can refer to it when designing an English program that meets the specific needs of existing and new company employees in the manufacturing industry.