Today consideration of knowledge management as a strategic need makes lack of enough knowledge the most significant issue. As a result, knowledge management is one of critical success factors in modern organizations and it is more important for project-based organizations. This article is the result of the survey done with thematic scope of the Knowledge Management basis in project-based companies, and the matter is studied among mid-level managers. By using Hadi Darami’s “success factors of Knowledge management in project-based companies”, a researcher-made questionnaire was devised. The Face and content Validity of the instrument was approved, the reliability of the instrument was approved by the reliability coefficient (Chronbach’s Alpha) of 0.916. In this article descriptive statistics, the kolmogroph-Smirnoph test, Spearman correlation coefficient, Binomial test, Friedman’s test and TOPSIS method have been used. The results show that the status of the organization infrastructure, Staff Motivation, and Human Resource Management factors are at a medium level and the status of the Strategy and Goal, Leadership and Management Support, Training, IT, and Culture factors are at a high level. Also, the priorities of the factors are: Strategy and Goal, IT, Organization infrastructure, Leadership and Management Support, Training, Culture, Human Resource Management, and Staff Motivation.