This paper presents multi-criteria methods (based on the Analytical Hierarchical Process (AHP), and Data Envelopment Analysis (DEA) used on the common ranking indexes) for ranking project activities according to several ranking indexes, and reviews ranking indexes of project activities for project management tasks. Ranking of project activities in one project is applicable for focusing the attention of the project manager on important activities. Selection of the appropriate ranking indexes should be done in accordance with managerial purposes: 1) Paying attention to activities throughout the execution phase and those in the resources allocation process in order to meet pre-determined qualities, and to deliver the project on time and within budget, i.e., to accomplish the project within the "iron triangle" 2) Setting priorities in order to share the managerial care and control among the activities. The paper proposes the use of multi-criteria ranking methods to rank the activities in the case where several ranking indexes are selected.