Introduction: Increased patient activation is associated with improved health outcomes; however, little is known about patient activation in people with end-stage kidney disease at the start of their dialysis journey. This study aimed to measure activation status changes over the first 4 months of dialysis.Methods: Prospective, longitudinal, and observational study. Incident patients initiating dialysis at 25 in-center hemodialysis and 17 home dialysis programs across three US states managed by the same dialysis provider completed the 13-item Patient Activation Measure (PAM-13) survey at baseline (month 1 after commencement of dialysis) and follow-up (month 4). The survey yields a score (0-100) that corresponds to four levels (1-4), with higher scores or levels indicating higher activation.Findings: One hundred eighty-two participants (139 center, 43 home) completed both baseline and follow-up surveys. Mean age was 60 AE 15 years, 40% female. Mean PAM-13 scores were 65.1 AE 16.8 and 64.8 AE 17.8 at baseline and follow-up, respectively; mean intraindividual change: À0.3 AE 17.3. The proportions of patients at levels 1-4 at baseline were 11%, 23%, 35%, and 31% respectively. At follow-up, 50%, 64%, 52%, and 37% of participants at levels 1-4, respectively, changed to a different PAM level (Spearman correlation = 0.47; p < 0.001). Home dialysis was associated with higher PAM scores when compared to in-center hemodialysis in multivariable analyses, adjusted for sociodemographic variables, comorbidities, and predialysis nephrology care (β = 5.74, 95% confidence intervals [CI]: 0.11-11.37 and 9.02, 95% CI: 3.03-15.02, at baseline and follow-up, respectively).Discussion: Although aggregated group scores and levels remained stable, intra-individual patient activation changed significantly during the first 4 months of dialysis. This novel finding is foundational to future projects aiming to design interventions to improve patient activation.