ISC 2021 World University Rankings announced Shiraz University second in the field of Agricultural Sciences (Agriculture, Forestry and Fishery major); and third in the field of natural sciences (The Earth and Environment major).

Dr. Mohammad Javad Dehghani, Head of ISC, declared that in 2019, ISC took the initiative to upgrade its regional ranking system into a global one which releases global university rankings annually. In ISC World University Rankings by Subject, the OECD hierarchical classification structure is used. In this structure, all subject areas are divided into 6 main categories and 42 subcategories (eventually 3 subcategories are left out). The 6 main categories in this ranking system are: Natural Sciences, Engineering and Technology, Medical and Health Sciences, Agricultural Sciences, Social Sciences and Humanities. The Head of ISC, also stated that the criterion for entering this year's ranking was being among the top 700 world universities and having at least 150 publications within the last three years.

The rankings performance indicators, shown in figure bellow, are grouped into four board areas: Research, Education, International Activity and Innovation.

According to the head of ISC, in Agricultural Sciences, Tehran University ranked first, Shiraz University ranked second, and Tarbiat Modares University ranked third. In the fields of Agriculture, Forestry and Fisheries, Tehran University, Shiraz University, Tarbiat Modares University, Isfahan University, and Tabriz University were ranked first to fifth respectively. Last but not least, in the field of Earth and Environment Sciences, Tehran University rankled first, Tarbiat Modares University ranked second, and Shiraz University and Tabriz University both ranked third.