Over the last few years there has been a rapprochement between Cognitive Linguistics and semantic theories of humour based on the notion of script or frame. By drawing on Ritchies version of the theory of frame-shifting (2005) and reviewing the cognitive linguistic account of humour, we shall demonstrate how the interpretation of jokes containing a metaphor or a metonymy involves two cognitive-pragmatic tasks: The completion of the metaphorical/metonymic mapping that results in a new frame, and the resolution of the jokes incongruity via a contrast with the surrounding frames of the joke. We also develop a classification of frame shifts according to their ontological structure (non-metaphorical/metonymic shifts and shifts based on metaphorical and/or metonymic reasoning) and the degree of the interpreters inferential activity (conceptual filling out and metaphor/ metonymy replacement). In doing so, we attempt to identify some of the defining features of humorous metaphors and metonymies, as well as other phenomena that may also characterise jokes. © John Benjamins Publishing Company.