Humans in the modern western society have become more and more flexible and dependent of technology. Flexibility has become one of the most significant expressions for the modern labour. The trend today seems to be that flexibility has become something that people need to do their work in a satisfying way. The past few years the demand for mobile services within the IT sector has increased avalanche-liked. People are becoming more and more dependent by computers, especially in work related situations. Due to these changes and the information technology’s affection on the society this thesis investigates the relation between usability and mobility. We have during the work of this thesis investigated the new technology Application Service Provider (ASP) and determined if this solution is mobile and at the same time usable in work situations, according to a checklist we have created. We have conducted an empirical study of an organisation that uses an ASP in their daily work. We have defined three types of mobility according to mobile informatics: the wandering, travelling and the visiting mobility. ASP is a mobile technology and therefore it can be used in all the types of mobile situations. We have discovered that ASP is mobile and at the same time usable only in the visiting category of mobility