The present study showed that using incidental learning tasks promoting structural/perceptual processing of targets it is possible to obtain a reliable spacing effect for nonsense auditory stimuli in a yes/no recognition memory task. These data extend and support previous findings (Cornoldi e Longoni, 1977; Russo e Mammarella, 2002) which detected a significant spacing effect with unfamiliar material such as non-sense shapes and non-words.