Inconsistent findings in the study of mood-related effects on memory are discussed in terms of the effects of arousal on cognitive processes. Manipulations used in studies of mood and memory typically affect arousal as well as affective valence. Although mood-related effects on memory are often interpreted in terms of valence, a consideration of arousal-mediated effects rarely occurs. In the motivation and performance literature, however, variations in arousal have been shown to interact with retention interval to affect immediate and delayed recall. Arousal is hypothesised to hinder some aspect of short-term memory but facilitate both the speed of processing and some aspect of storage for long-term retrieval. The construct of arousal is also used more generally to organise the effects of stable individual differences in personality and a variety of motivational manipulations on cognitive performance. The implications of these effects of arousal for the pattern of inconsistent findings in the study of mood-related effects on memory are discussed in terms of the general effects of arousal on cognitive performance.