Abstract Melamine-urea-formaldehyde (MUF) resin is commonly used in the production of wood-based panels. It can replace urea-formaldehyde (UF) resin particularly to improve wood panel properties under high humidity conditions. This paper presents a life cycle assessment (LCA) study of the production of MUF resin through a case study conducted in Brazil. The assessment of 1 kg of MUF resin included two main stages: raw material supply and MUF resin manufacturing. A detailed inventory of MUF resin was obtained from technical visits to a Brazilian producer (foreground system), as well as from literature reviews (mainly background systems). The potential environmental impact assessment phase was assessed by applying two methods and seven impact categories: CML (abiotic depletion, acidification, global warming, eutrophication and photochemical oxidation) and USEtox (ecotoxicity and human toxicity). The raw material supply stage was responsible for most of the impacts, except for the toxicological impact categories. Nearly all of the raw material supply hotspots are related to the production of melamine (9–61% of impacts) and urea (3–72% of impacts). The MUF manufacturing stage was significantly more important for ecotoxicity (84% of impacts) and human toxicity (72% of impacts) due to local formaldehyde emissions. Improvement scenarios were developed and the addition of up to 10% of melamine was suggested for the production of MUF resins. MUF resin was compared with UF resin and the results showed that MUF can replace UF resin because of its lower contribution to photochemical oxidation, ecotoxicity and human toxicity.