In this study, the performance of mortar incorporating biopolymer resin derived from cardanol and fly ash was evaluated. Biopolymer resin, is a natural polymer derived from cashew nut shells, can be used as a replacement for cement. Researchers are looking for alternatives to fillers and resins due to depleting petroleum reserves and inability to biodegrade. While some strategies for improvement of natural composites were effective, they still fall short of the performance of synthetic resins. The polymeric composite terms, industrial waste products can be used as filler material. Industrial waste such as fly ash, GGBFS can be used to produce new high performance polymer products. The reuse of industrial waste for biopolymer mortar is a sustainable option to the environment. The present study focuses on investigating the biopolymer mortar mechanical, chemical and durability properties. In this study, the resin content is 14, 16 and 18% with combination of filler material fly ash as 16, 18, and 20%. Based on Research Surface Methodology (RSM), design of experiments was suggested by Design Expert Software. The results showed that the incorporation of CNSL resin and fly ash improved compressive, tensile strength, and durability of the mortar. The combination of 18PM18 has showed increased strength when compared to cement mortar and other combinations. Cashew nutshell biopolymer resin can be utilized as a binder, while fly ash can be used as a mineral filler.