Aim The aim of the present study was to evaluate the relationship between sedentary time and declines in kidney function among community‐dwelling older adults. Methods Participants comprised 10 242 community‐dwelling older adults who were participating in the National Center for Geriatrics and Gerontology – Study of Geriatric Syndromes. Sedentary time was determined by asking participants to record the total amount of hours usually spent sitting each day, with values divided into quartiles of 0 to <4 h (reference), 4 to <6 h, 6 to <8 h and ≥8 h of sitting time per day. The estimated glomerular filtration rate was determined according to creatinine levels, and participants were classified into two categories: ≥60.0 or <60 mL/min/1.73 m2. Results After multivariate adjustment, the highest quartiles of sedentary time showed a higher rate of kidney function decline than those in the lowest quartile (odds ratio 1.42, 95% CI 1.02–1.37). In addition, participants with a history of cancer (odds ratio 1.18, 95% CI 1.01–1.39) or hypertension (odds ratio 1.38; 95% CI 1.07–1.60) had significantly increased risks of kidney function decline in the highest sedentary time group, regardless of multivariate control. Furthermore, analyses showed an increased risk of kidney function decline for a history of both cancer and hypertension (odds ratio 2.02, 95% CI 1.08–3.80). Conclusions A higher level of sedentary time was associated with kidney function decline among community‐dwelling older adults. Geriatr Gerontol Int 2017; 17: 730–736.