The SEO Classification is arranged in a hierarchical structure.
It has 5 divisions, 18 subdivisions, 107 groups and 594 classes.

The divisions and subdivisions are:

Division 1 Defence
610000 Defence
 
Division 2 Economic Development
620000 Plant Production and Plant Primary Products
630000 Animal Production and Animal Primary Products
640000 Mineral Resources (Excl. Energy)
650000 Energy Resources
660000 Energy Supply
670000 Manufacturing
680000 Construction
690000 Transport
700000 Information and Communication Services
710000 Commercial Services and Tourism
720000 Economic Framework
 
Division 3 Society
730000 Health
740000 Education and Training
750000 Social Development and Community Services
 
Division 4 Environment
760000 Environmental Policy Frameworks and Other Aspects
770000 Environmental Management
 
Division 5 Non-Oriented Research
780000 Non-Oriented Research