This thesis is an investigation of whole-body vibration (WBV) on mobile machines within the steel making industry. Six degrees-of-freedom chassis vibration was quantified for five vehicle types and analyzed according to methods outlined in ISO 2631-1 (1997). One of the mobile machines (Pot Hauler) was identified to have elevated levels of WBV, and six daily operating profiles were created for use in a laboratory study, which led to the development of methodologies for optimal seat retrofitting. The results of the laboratory study indicate that one seat may not be best for all vibrations encountered daily by mobile machine operators, and that operator sex, as well as vibration profile, will affect the best seat selection.