ABSTRACT: Rationale & Objective:Chronic kidney disease (CKD) care is often fragmented across multiple health care providers. It is unclear whether patients rely mostly on their nephrologists or non-nephrologist providers for medical care, including CKD treatment and advice. Study Design:Cross-sectional study. Setting & Participants:Adults receiving nephrology care at CKD clinics in Pennsylvania. Predictors:Frequency, duration, and patient-centeredness (range, 1 [least] to 4 [most]) of participants' nephrology care. Outcome:Participants' reliance on nephrologists, primary care providers, or other specialists for medical care, including CKD treatment and advice. Analytical Approach:Multivariable logistic regression to quantify associations between participants' reliance on their nephrologists (vs other providers) and their demographics, comorbid conditions, kidney function, and nephrology care. Results:Among 1,412 patients in clinics targeted for the study, 676 (48%) participated. Among these, 453 (67%) were eligible for this analysis. Mean age was 71 (SD, 12) years, 59% were women, 97% were white, and 65% were retired. Participants were in nephrology care for a median of 3.8 (IQR, 2.0-6.6) years and completed a median of 4 (IQR, 3-5) nephrology appointments in the past 2 years. Half (56%) the participants relied primarily on their nephrologists, while 23% relied on primary care providers, 18% relied on all providers equally, and 3% relied on other specialists. Participants' adjusted odds of relying on their nephrologists were higher for those in nephrology care for longer (OR, 1.08 [95% CI, 1.02-1.15]; P = 0.02), those who completed more nephrology visits in the previous 2 years (OR, 1.16 [95% CI, 1.05-1.29]; P = 0.005), and those who perceived their last interaction with their nephrologists as more patient-centered (OR, 2.63 [95% CI, 1.70-4.09]; P < 0.001). Limitations:Single health system study. Conclusions:Many nephrology patients relied on non-nephrologist providers for medical care. Longitudinal patient-centered nephrology care may encourage more patients to follow nephrologists' recommendations.