The competent legislation based on the real needs of the society is an effective element in improving the quality of legislation and preventing the social and economic costs arising from poor quality legislation. Legislative needs assessment is based on citizens' right to determine their fate and to exercise their sovereignty. However, it is not possible to scrutinize the views of all citizens and the legislative needs assessment of all citizens in all matters, and also, along with the necessity to legislative prioritization of citizens’ and receiving their willing in the area of legislation, it is essential to collect stakeholders' views on the one hand and the opinions of experts and relevant specialists on the other hand. The main question in this research is that in Iran's legislative system, to what extent, legislative needs assessment is considered as an essential element in the competent legislation. Accordingly, in the form of a descriptive-analytic research, the result was that, firstly, the legislative system of the country regarding the legislative needs assessment has a weak literature and poor experience and is also neglected in legislative procedures, so that even, in practice, little value is given to those laws and regulations enacted based on the legislative needs assessment. Secondly, in order to lay down competent, efficient and responsive needs of the society, there is no choice but to strengthen the dimension of needs assessment in legislation. Thirdly, the legislative needs assessment is different from populism in the field of legislation, and on the pretext of populism, legislative needs assessment should not be put away.