Abstract
The study aims at identifying the factors affecting the effectiveness of the internal control system in the Income Tax
Departments in Palestine. Also, determining the impact of both (Control environment, Risk assessment, Control activities,
Information & Communication systems, monitoring Internal Audit Department activity, Information technology
used) on the effectiveness of the internal control system in the Income Tax Departments in Palestine. To achieve the
objectives of the study, the researcher used the descriptive methodology. To determine the accuracy of the questionnaire
with the subject of the study and its objectives, after testing its Validity and Stability, it was applied to all the individuals
of the sample that are suitable for the study which includes two categories. The first category consisted of (66) employees
of Income Tax Departments selected in the method of the sample intent. While the second category consisted of (15)
employees of the Internal Audit Department of the Ministry of Finance and Planning, from whom the data was collected
using the comprehensive inventory method, where (64) questionnaires were retrieved from Income Tax Departments
employees and (13) questionnaires from Internal Audit Department staff, collected, encoded, entered into the computer
using the social statistical science package program, and processed using the social statistical science package program.
The results of the study showed that the most important factors affecting the effectiveness of the internal control system
are: an appropriate separation of tasks for department staff (separation of assessment and auditing functions). It
also showed that the least effective factors on the effectiveness of the internal control system are; the availability of an
approved professional framework (policies, procedures, training, and department) to regulate the risk management process
in the Income Tax Departments. Accordingly, the researcher recommended that there is an urgent need to establish
a specialized risk management department in the General Administration of Income Tax, because of its importance in
controlling the risks that may be faced by Income Tax Departments and reducing them to acceptable proportions.