The rheological characterization of a wide variety of materials used in computer hardware is described. The materials and applications presented include liquid crystal polymers for components, solder paste for surface mounting of integrated circuits, screen printable polyimide for dielectric patterns, new photosensitive polyimide to reduce processing steps, hot-melt adhesive for temporary bonding, pressure-sensitive adhesive for permanent bonding of optical recording disks, bearing grease for magnetic recording disk drive spindles, fluoropolymer lubricants for magnetic recording disks, magnetic particle suspensions for magnetic tape and disks, toner for laser printing, thermoplastic polymer for rapid prototyping, and cathode paste for rechargeable lithium batteries. Rheological tests appropriate for each of the materials were designed to provide key information about its performance in the intended application. This overview provides insight into the relation between interpretation of rheological test data and materials performance in engineering applications as well as for process control. Rheology is essential to the development of computer hardware and peripheral devices.