Objective: Analyze the relationship between the Mental Workload (MWL) and Health-re-lated quality of life (HRQoL), perceived by workers working in oncology and palliative care units in one region of Chile. Materials and methods: Non-experimental, correlational, cross-sectional research and quantitative approach. A number of 110 health workers were counted (doctors, registered nurses, psychologists, among others), corresponding to 92 % of the total population. For the collecting data, a three-part divided instrument was used: a) Biological and socio-de-mographic background (such as age, sex); b) Mental Workload Scale (ESCAM), which was adapted and validated to Chilean population; and c) The Questionary of Life Quality related to Health SF-36v2, which has been validated and standardized to Chile. To the descriptive, statistical and inferential analysis, the software SPSS version 18.0 was used. The Commit-tees of Ethics-Scientific from the Catholic University of Maule and the Health Service of Maule authorized the research. Results: Participants perceive a mid-high global mental load. On the other hand, they perceive better results on the physical health component (x: 76.72, SD 9.75) versus the mental health component (x: 71.13; SD: 6.38). In addition, there are relationships with statistical importance (p≤0.05), between mental workload and life quality related to health. Conclusions: This study allows us to affirm that the demands to oncological workers who perceive mental workload report worse results in their life quality related to health.