Background: Stroke is a serious medical condition potential that affects humans and requires special attention. The treatment of stroke is highly dependent on patients' knowledge and adherence in undergoing rehabilitation. Knowledge about medical rehabilitation will determine the level of patients' adherence undergo medical rehabilitation. The study aimed to find the correlation between patients' knowledge and adherence to chronic stroke patients undergoing medical rehabilitation.Methods: This is an observational analytic study conducted in the executive medical rehabilitation policlinic at dr. Zainoel Abidin Hospital. Seventy-four respondents were selected by the non-probability sampling technique and accidental sampling method. Two questionnaires were used, namely the "Overview of Familial Behaviour towards Stroke Patients in Rehabilitation Efforts" questionnaire and the "Correlation of Family Support with Stroke Patients Rehabilitation Adherence" questionnaire. Data were analyzed using Chi-Square statistical test.Results: 45.9% of respondents had good knowledge and compliance, 23% of respondents had average knowledge and compliance, and 9.5% of the respondents had poor knowledge and compliance.  Data analysis showed a significant correlation between patients' knowledge and level of adherence in undergoing medical rehabilitation.Conclusion: Increasing patients' knowledge about medical rehabilitation is crucial to improve patient's adherence in undergoing medical rehabilitation.