Three experiments investigate the effects of mixing items of different types in the same list. Experiments 1 and 2 compare the immediate serial recall of high- and low-frequency words in pure and alternating lists. In pure lists high-frequency words are better recalled, but in alternating lists the two types of words are recalled at intermediate, and identical, levels. Experiment 3 compares the recall of words and nonwords. In pure lists nonwords are recalled substantially less well than words. In alternating lists nonwords gain a substantial recall advantage compared to pure lists but are still less well recalled than words, which are recalled at identical levels in both mixed and alternating lists. The results refute item-based redintegration accounts of frequency effects in immediate serial recall and provide evidence for the importance of inter-item associative mechanisms.