Mladinska knjiga d d (MK) is the largest publishing house in Slovenia, which in 2002 published 325 titles, alongside an additional eight titles for the Croatian market, and 67 cassettes, CD audio records and CD-ROMs. The print-run in 2002 came to 1,313,000 units. Exports have increased recently with the re-opening of the Croatian market.

MK offers extensive and varied coverage of poetry (the collection Lirika, established in 1970, includes around 100 titles of world poetry translations), prose and professional literature. However, its most significant publishing and research project is without doubt the Encyclopaedia of Slovenia, which is issued in 16 volumes.

MK runs several bookstores, the largest of which - Konzorcij Bookstore - hosts the Frankfurt after Frankfurt Book Fair and Bologna after Bologna Children's Book Fair. See Mladinska knjiga Bookstores.

MK is also the main publisher of magazines for children (Cicido, Ciciban, PIL), and school students (PILplus), runs the educational project Vesela šola ('Merry School') and publishes GEA magazine.

MK also bestows the annual Levstik Award for children's literature and runs two gallery spaces.