OBJECTIVES: Although previous studies have reported lower mortality and morbidity in people with higher daily step counts, the association between frailty and objectively measured step counts has not been evaluated well. We investigated the association between step counts and prevalence of frailty in community-dwelling older adults. DESIGN: A cross-sectional study. SETTING: The Kyoto-Kameoka study in Japan. PARTICIPANTS: We used data of 3,616 Japanese older adults, aged 65 years or older, with valid daily step count data, obtained by an accelerometer-based pedometer. MEASUREMENTS: The step count during 4 or more days was objectively obtained by a validated triaxial accelerometer. Participants were classified by quartiles (Qs) based on their step counts. Frailty was defined using the Fried phenotype (FP) model and the Kihon Checklist (KCL). We evaluated the association between prevalence of frailty and step counts using multivariate logistic regression and the restricted cubic spline model. RESULTS: Mean step counts across low-to-high Qs of distribution were 1,759, 2,988, 4,377, and 7,200 steps/day, respectively. The prevalence of frailty, as defined by the FP model and KCL, was 11.3% and 26.8%, respectively. After adjusting for confounders, there was a negative association between the odds ratio (OR) and prevalence of frailty, as defined by the FP model among people with higher step counts (Q1: reference; Q2: OR = 0.73; 95% confidence interval (CI) = 0.56-0.96; Q3: OR = 0.56; 95% CI = 0.42-0.76; and Q4: OR = 0.41; 95% CI = 0.30-0.57; P for trend <.001). The mean step count of the population was 4,081. The OR of frailty for a 1,000-steps/day increment was 0.74 (95% CI = 0.58-0.91) and 0.85 (95% CI = 0.72-0.97) below 4,000 steps and above 4,000 steps, respectively. In the spline model, this relationship was similar between the FP model and KCL. CONCLUSION: These findings suggest that slightly increasing the current step count, as by 1,000 steps/day (about 10 minutes of activity), may potentially prevent frailty. J Am Geriatr Soc 68:2310-2318, 2020.