Background: Denture care is a crucial aspect of oral hygiene, particularly in geriatric patients who wear removable partial dentures. Poor denture hygiene can lead to various oral health issues, including periodontal disease. This study aims to evaluate the association between denture care habits, oral hygiene knowledge, and the periodontal status of geriatric patients in Bhagalpur District, Bihar. Materials and Methods: A total of 75 geriatric patients wearing removable partial dentures were included in this study. The study was conducted over a period of 6 to 9 months. Participants were assessed for their denture care habits, oral hygiene knowledge, and periodontal status using a structured questionnaire and clinical periodontal examination. The periodontal examination included measures of plaque index, gingival index, and pocket depth. Data were analyzed using descriptive statistics and correlation analysis. Results: The average age of the participants was 68 years. Approximately 60% of the patients demonstrated inadequate denture care habits. Oral hygiene knowledge was found to be moderate in 45% of the participants, while 35% had poor knowledge and 20% had good knowledge. Periodontal status was significantly associated with denture care habits and oral hygiene knowledge. Patients with good denture care habits had a lower plaque index (mean = 1.2) and gingival index (mean = 1.0) compared to those with inadequate denture care habits (plaque index mean = 2.5; gingival index mean = 2.3). A positive correlation (r = 0.65, p < 0.01) was observed between oral hygiene knowledge and periodontal health status. Conclusion: The study highlights the importance of adequate denture care and oral hygiene knowledge in maintaining periodontal health among geriatric patients with removable partial dentures. Improved education on denture care and regular dental check-ups are recommended to enhance oral health outcomes in this population.