This study aims to determine whether the varible social media usage has a positive effect on purchase intention in Martha Tilaar's cosmetics products, does the variable social media usage have a positive effect on E-WOM, does the EWOM variable usage which is mediated by E-WOM has a positive effect on purchase intention on cosmetics products of Martha Tilaar. The sampling technique in this study used convenience sampling. Respondents in this study amounted to 392 respondents. Then, to analyze the data used PLS-SEM with the help of SmartPLS applications. The results showed that the use of social media did not have a positive effect on buying interest in Martha Tilaar's cosmetics products, the use of social media had a positive effect on E-WOM, E-WOM had a positive effect on buying Martha Tilaar cosmetic products and the use of social media mediated by E-WOM has a positive effect on buying interest in Martha Tilaar cosmetics products.