The collection’s holdings consist of 4,060,820 specimens (including 2,120 primary and 46,453 secondary types) representing over 53,000 described species. Over the last 5 years, an average of 67,000 new specimen accessions have been added annually to the collection. Holdings of special taxonomic or historical importance include:
- Insects (especially Coleoptera) collected by Otto Luger (late-1800s)
- C.E. Mickel Mutillidae collection – one of the best in the world; 27,000 specimens and 282 primary types
- J.E. Guthrie collection of Collembola (springtails)
- O.W. Oestlund and A.A. Granovsky collections of Aphididae
- A.G. Richards owlet moth collection (Lepidoptera: Noctuidae)
- R.D. Price collection of Mallophaga (Phthiraptera) lice, containing more than 220,000 slide-mounted specimens
- T.N. Anathakrishnan thrips (Thysanoptera) collection
- R.W. Gundersen & St. Cloud State University Insect Collection; amassed by Dr. R.W. Gundersen, containing more than 100,000 specimens, with emphasis on aquatic Coleoptera (beetles) and aquatic Hemiptera (true bugs)
- The Dr. James E. and Mary F. Sublette collection of Chironomidae – one of the best chironomid collections in the world, containing more than 87,000 slide-mounted specimens, which includes scores of new species awaiting description
- J.H. Harstaad & Cedar Creek Ecosystem Science Reserve (U of MN) Insect Collection
- US Geological Survey National Water Quality Laboratory (NWQL) macroinvertebrate collection
- W.C. Scharf Siphonaptera (flea) collection
- One of the word’s largest caddisfly (Trichoptera) collections, containing more than 2000 species, and comprised of more than 560,000 bar-coded and databased specimens
- Dr. David Ahrenholz Collection of Lepidoptera
- St. John's University Insect Collection
- The Mike McPhee Insect Collection donated by Amy Okaya
In addition to these historically important taxonomic holdings, the collection houses material from throughout Minnesota, the Upper Midwest, and the United States. Much exotic material has been added from research expeditions abroad, including material from Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, French Guiana, Mexico, Nicaragua, Peru, Trinidad & Tobago, and Venezuela in the New World and Australia, Cameroon, Ghana, Indonesia, Kenya, Malaysia, Russia, and South Africa in the Old World.