Deroceras praecox is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Agriolimacidae.

Later Wiktor (1973) realised that one of the forms of D. praecox that he had distinguished was synonymous with Deroceras rodnae, described slightly earlier by Grossu & Lupu (1965).

But the other form with a spiral end to its penis occupied a distinct range in the Sudeten mountains and neighboring areas; this is what is called D. praecox nowadays.

The coloration of the body of this slug is usually snowy white or off-white mottled with grey (Wiktor, 2000).

It is not listed in the IUCN red list - and thus is not evaluated (NE)[1] It occurs in: A closely related form of uncertain taxonomic status occurs in the uplands south of Dresden, Germany (Hutchinson & Reise, 2009).