I. Abstract The thesis deals with the concept of time and its conceptualisation in the Czech language. It is based on the theory of conceptual metaphor and the theory of linguistic worldview. Within the field of cognitive linguistics, the theory of conceptual metaphor is mainly applied in the identification of the source domains of metaphors used for language expression of the target domains. The first part of the thesis deals with the reflection of the "time" phenomenon, with its non- linguistic concept. Attention is paid to the concept of the cyclical and linear time. The second part aims to identify metaphors used in Czech for the expression of time relations and for the expression of the time phenomenon. The paper analyses the language plane in order to find such metaphors. It employs semantic and etymological analysis of words used when expressing the notion of time, i.e. nouns, adjectives, verbs, prepositions, and interjections.