With detailed result analysis of this empirical research, it can be noticed that five most important factors of information system successfulness mentioned by the information system managers are mostly consistent with those mentioned by user manager. However, there are two exceptions: Factors of relations and communication between users and information technology specialists have been rated as more important than the factor of understanding of user’s needs, while the user managers have rated the opposite. Factor “providing training for users” has been pointed by the user managers as less important than the factor of output size and the factor of business effects from computer support, while information system managers are pointing out the opposite. Attention should especially be devoted to the fact that the factor of relation between user and information system specialist has been rated as the third most important factor of successfulness by the information system specialists, and as irrelevant by the staff of information systems and users, which points to the possibility of a problem is in the assessment process of information system successfulness between the information system manager and other users connected to the information system.