In this work, we present a system and methodology for using mobile phones for monitoring physical activities of a user, and its applications in assisting elderly and people with need for special care and monitoring. The method is based on processing acceleration data provided by accelerometers integrated in mobile phones. This information is sent to a monitoring server, analyzed and presented as different health related factors for assistance, monitoring and healthcare purposes. A monitoring agent can use a desktop application to observe pattern of physical activities of several users in a live manner, and receive warnings in case of unexpected physical conditions. The data can be also stored offline for longer term analysis of physical behaviour and health. The desktop application also provides different options for managing, browsing, and searching activity related data.