Hydration status is a person's body condition that describes the amount of water in the body. Poor hydration status can affect decision-making and cognitive performance in the form of concentration levels, leading to lower productivity and increasing the risk of work-related accident. The objective of this study was to determine the hydration status and  its relationship with the concentration level of rubber farmers in South Lampung. this research was an observational study with a cross-sectional design. The population in this study was 80 rubber farmers in South Lampung. The sampling method used was concecutive sampling with inclusion and exclusion criteria and obtained a sample of 67 respondents. The independent variable in this study was hydration status and the dependent variable was the concentration level. Data were analyzed using a Chi-square test with α value of 5%. Statistical analysis showed that 37 respondents (55.2%) were dehydrated and 36 respondents (53.7%) had a low concentration level. The results of bivariate analysis between hydration   status  and  concentration level showed the p-value = 0.012. There was a significant relationship between hydration status and concentration level in rubber farmers in South Lampung. It is very important to educate the  farmers about  healthy hydration to help them having a good concentration level at work.