Intruduction : This research investigates the implications of the transition from the metaphysical concept of justice to its social concept in law. Throughout 19^th century and 20^th century, the metaphysical justice as a basis for law was criticized. As a result, social justice was emphasized as a basis for law. This transformation brought about some fundamental changes in law. Since labor law was deeply affected by these changes, the implications of the transition from the metaphysical concept of justice to its social concept in general was investigated and the transition’s practical consequences for the Iranian laws on employment and labor relations were examined.

Method: This research is done through content analysis. There is no sampling and the research was done through census technique and all the statistical population is examined. The analysis unit is subject – single statement about something. The content of the Iranian laws related to labor relations from 1928 to 1990 was examined focusing on the five main aspects of social justice and five main aspects of metaphysical justice. The subject units are specified based on their correspondence and compatibility with the special structural definition of content. Their distinction is conceptual based on having desirable structural characteristics in comparison to the irrelevant remainder materials.

Findings: From 1928 to 1990, the social justice concepts’ usage has increased. Because of this and a decrease in metaphysical justice concepts in proportion to social justice, the following changes have occurred in the Iranian laws regarding labor relations: from 1928 to 1990, there is an increase in taking into consideration distributional justice, social functions of law, social order, civil rights and flexibility of law.

Discussion: From 1946 on, the laws are based on civil rights instead of individual interests. They are more flexible and are changed toward the worker’s interests and their supportive aspects have increased.