OBJECTIVE: To investigate the within-day test-retest reliability of the & Go" (TUG) test in patients with advanced Chronic Obstructive Pulmonary (COPD), Chronic Heart Failure (CHF), and Chronic Renal Failure (CRF). Cross-sectional. SETTING: Patients' home environment in the South-East the Netherlands. PARTICIPANTS: 235 subjects (64% men, median [IQR] age years; body mass index [BMI] 25.6 [22.8-29.4] kg.m-2) with advanced COPD CHF (n=68) or CRF (n=72). INTERVENTIONS: Not applicable. MAIN OUTCOME Time to complete the TUG test. Three trials were performed on the same the same assessors. The Intraclass Correlation Coefficient (ICC), kappa coefficient, Standard Error of Measurement (SEM), and absolute and Minimal Detectable Change (MDC) values were calculated. RESULTS: Good was observed, in general, for both the total sample and subgroups (COPD, CRF) with ICC values ranging from 0.85 to 0.98, and kappa coefficients to 1.00. However, statistical improvement occurred in the total sample first to the second trial with large limits of agreement (mean CI] -0.97 [+3.00 to -4.94] seconds, p<0.01). The third trial added information to the first two trials. For the total sample, values of SEM 1.6 seconds, MDC95% around 4.5 seconds, and MDC95%% around 35% were the first two trials, with close values found for the subgroups. TUG test is reliable in patients with advanced COPD, CHF, or CRF after trials. Values of SEM and MDC may be used in daily clinical practice populations to define what is expected and what represents true change repeated measures.