In this paper we describe the implementation of the first structured resource of semantic derivational links for Latvian, basing it on the largest online dictionary Tēzaurs.lv and linking it to the Latvian WordNet. We separate two kinds of derivational links: semantic derivation links between senses and morphological derivation links between lexemes. The semantic links between senses are defined as a pair of semantic labels assigned to both ends of the link. The process of semantic linking involves revising the sense inventory of both the base word and the derivative, defining semantic labels for lexemes of four basic word classes – nouns, verbs, adjectives and adverbs, and adding the appropriate labels to the corresponding senses. We exemplify our findings with a detailed representation of sense relations between a base verb and its nominal derivatives.