A development of a verb valency lexicon for Latvian has been recently started. The chosen approach combines and supplements the experience of similar lexical resources developed for other languages. The paper describes our approach to the verb valency annotation—the valency layers (syntactic and semantic valency, selectional restrictions) and the set of the semantic roles. The annotation process using an online tool developed for the valency annotation is also briefly described. From the annotated corpus examples, the valency patterns (models) for each verb are generated considering only the core semantic roles. As a result of this work, a summarized information of valency patterns for each verb will be available, as well as a corpus of the annotated examples. Currently, more than 150 verbs (more than 16 000 sentences) have been annotated using data from the Balanced Corpus of Modern Latvian.