Abstract: Background and Objectives: Concern of environment due to global warming is one of the reasons for this study to be conducted. However, there are lacked of studies to mitigate this global problem. Therefore, this study was aimed to determine the carbon sink in seaweed, water and sediment from seaweed, Glacillaria changii culture. Materials and Methods: The study was conducted in grow-out pond at Southern (Johor State) and Northern (Kedah State) of Peninsular Malaysia. The carbon content in water was determined using total organic carbon (TOC) analyzer, while combustion method using solid sample module (SSM) machine was used for sediment and G. changii samples. Results: The results showed that total carbon (TC), total organic carbon (TOC) and total inorganic carbon (TIC) in seaweed sample were higher in northern region as compared to southern region. This indicates that seaweed has high potential value in sequestering carbon dioxide (CO2) in environment which further can be used to mitigate the global warming effect phenomenon. Conclusion: Thus, G. changii are not only showed high economic value to the industry but also potentially play an important role as carbon sink which they can store carbon.