This study aimed to identify the impact of Computerized Management Information Systems on the performance of workers in the Establishment of Telecommunication in Tartous, to achieve the study's objectives a Questionnaire of (28) paragraphs –for the purpose of data collection and measurement of study variables- was designed and developed. The study made several results ,and the important results ;there is a significant relationship between operation and management requirements of Computerized Management Information Systems (physical ,programmatic ,human and organizational) and the performance of workers in the establishment , but there isn’t a significant differences between the perceptions of respondents on the impact of computerized Management Information Systems on the performance of workers due to the demographic variables(Level of Scientific, Gender ,Place of work, Functional level ) .