A materials management system (10) comprises a materials database (12) for storing information relating to the nature identity and location of each item of material on a site. A mobile data processing device (14) is provided, having a data scanner (16) for scanning machine-readable identification information provided in an identification tag attached to an item of material. A GPS receiver (18) is operatively connected to the mobile data processing device (12) for obtaining the GPS coordinates of the item of material. The mobile data processing device (14) transmits the GPS coordinates and the identification information to the materials database (12) so that the location of each item of material on site can be tracked. The materials database (12) can be accessed online from anywhere in the world via satellite link (20) (or internet) using any suitable desktop personal computer (22). The materials management system has particular application to a construction site, and sites where intrinsically safe systems are required.