With an ever increasing number of mobile services, meaningful audio notifications could effectively inform users of the incoming services while minimising undesired and intrusive interruptions. Therefore, careful design of mobile service notification is needed. In this paper we evaluate two types of audio (auditory icons and earcons) as mobile service notifications, by comparing them on 4 measures: intuitiveness, learnability, memorability and user preference. A 4-stage longitudinal evaluation involving two lab experiments, a field study and a web-based experiment indicated that auditory icons performed significantly better in all measures. Implications for mobile audio notification design are presented. Author Keywords Mobile audio notifications, mobile services, earcons, auditory icons, intuitiveness, learnability, memorability. ACM Classification Keywords