Is the format of semantic representation for idiomatic expressions different from that for words or literal phrases? Do the semantic characteristics of idiomatic expressions influence their processing? This study examined the influence of the compositionality dimension on the processing of idiomatic expressions. It was hypothesized that decomposable and nondecomposable idiomatic expressions are represented differently in memory and that this difference affects the processing time of idiomatic expressions. In 2 experiments, participants read sentences containing decomposable idioms, nondecomposable idioms, or control expressions and performed a lexical decision task on figurative targets presented 0 msec, 350 msec, or 500 msec after reading. Results demonstrated a clear effect of compositionality on the activation of figurative meaning: decomposable idiomatic expressions were processed sooner than nondecomposable idiomatic ones. These results are discussed in the framework of the hybrid model (Titone & Connine, 1999) and the construction-integration (CI) model (Kintsch, 1998) (Stephanie Caillies and Kirsten Butcher)