DeriNet is a lexical network which contains derivational relations in Czech modeled as an oriented graph. Nodes correspond to Czech lexemes (a lexeme is a single lemma, possibly with only a subset of its senses – homonyms may have different derivations and are thus represented by several lexemes) and edges represent derivations between them. DeriNet 1.0 contains 968,967 lexemes with 965,535 unique lemmas; connected by 715,729 derivational links. Lexemes in DeriNet 1.0 are sampled from the MorfFlex dictionary.