The study aimed to study the relationship between the use of the Syrian mobile telecommunications companies' customers for social media (Facebook) for marketing purposes, and their ability to influence customers at each stage of the purchase process, which includes:: the generation phase of the need, the stage of the search for alternatives, the stage of evaluating the alternatives, the stage of making the purchase decision, and the post-purchase phase. In order to achieve this, a main hypothesis was formulated with five sub-hypotheses. The researcher used the questionnaire technique to collect the data analyzed using statistical tests, the most important being the one-sample T. test and the Pearson Correlation test. The researcher has reached several results, the most important of which is: There is a strong positive correlation between the use of the Syrian mobile telecommunications companies' customers for social media (Facebook) for marketing purposes and all stages of the purchase process.