BACKGROUND: Osteoarthritis (OA) is a pathology that frequently affects the geriatric population. OBJECTIVE: To investigate the extent to which pain, functionality, and quality of life change over the progression of OA grades. METHOD: The study included 161 patients with bilateral OA, whose disease stages ranged from 1 to 4 according to the Kellgren-Lawrence radiographic classification system. Pain was assessed using the Visual Analog Scale (VAS), functionality using the two-minute walk test and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, and quality of life using the Nottingham Health Profile (NHP). RESULTS: There were significant differences between the groups in terms of age, weight, and body mass index. The VAS, two-minute walk test, and WOMAC scores also significantly differed between the groups (p < 0.05). There was a significant difference between the groups in all domains of the NHP, except for energy (p < 0.05). The two-minute walk test score was negatively correlated with all the remaining evaluation parameters (p < 0.05). No correlation was found between the energy domain of the NHP and body mass index, the VAS score, the two-minute walk test distance, or the total WOMAC score (p > 0.05). CONCLUSION: After grade 1, the functional impacts of OA on patients increased by an average of four times. Pain was one of the most basic symptoms, the severity of which started to increase in grade 2. With the added effect of diminishing walking capacity over time, the reduction in the quality of life of the patients accelerated as the OA grade progressed.