Sixty-eight undergraduate students were randomly allocated to one of four task conditions and required to worry about a topic of importance to them while simultaneously performing the task to which they had been allocated. The tasks differed in their ability to interfere with worrying. Generation of random letters was the only task to interfere significantly with the ability to worry. There was a nonsignificant tendency for articulatory suppression to produce some interference with worrying while visuo-spatial tasks did not affect the ability to worry. There was no difference in results between self-reported worriers and non-worriers. The results seem to indicate that worry primarily utilises the phonological aspect of the central executive of working memory.