Ergonomic Tridimensional Analysis (ETdA) is a new ergonomic approach that makes possible the identification and description of several ergonomic contexts defined by common areas where clients or consumers are subject to similar activities normally carried out by professionals. The development of this decision tool includes several steps, such as conceptualization of the problem, definition of the three ETdA dimensions and observation tools, data collection, and weighting the results leading to ergonomic intervention proposal. The software, named ETdAnalyser, is proposed to provide the ergonomist or analyst a fast and simple way of collecting and analysing data. This system is considered to be a decision-making support tool for ergonomic intervention, representing a relevant contribution to the advance of the ergonomics field.