The Ss memorized a long-term set (LT set) of 20 words before participating in a recognition memory test. On each trial Ss were given a new short-term set (ST set) of from one to four words or one to four digits. The Ss gave a positive response to a test item that was a member of either the ST or the LT set and gave a negative response to a test item not in either set; both words and digits were used as test stimuli. The results indicated that reaction time (RT) to positive test items from the ST set was an increasing function 0f the size of the ST set; the same was also true for negative responses to test digits when the ST set was composed of digits. RT to other test stimuli, however, did not depend on ST set size. These results are consistent with the view that Ss access long-term memory (LTM) and short-term memory (STM) simultaneously rather than sequentially. The results also showed that Ss responded more quickly to test items from the LT set when the ST set contained digits than when it contained words. Negative test items that were words, however, were rejected more slowly when the ST set contained digits than when it contained words. These results suggest that the search of LTM was affected by the contents of STM.