BACKGROUND: PRO-CTCAE is a library of items that measure cancer treatment-related symptomatic adverse events (NCI Contracts: HHSN261201000043C and HHSN 261201000063C). The objective of this study is to examine the equivalence and acceptability of the three data collection modes (Web-enabled touchscreen tablet computer, Interactive voice response system [IVRS], and paper) available within the US National Cancer Institute (NCI) Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) measurement system. METHODS: Participants (n = 112; median age 56.5; 24 % high school or less) receiving treatment for cancer at seven US sites completed 28 PRO-CTCAE items (scoring range 0-4) by three modes (order randomized) at a single study visit. Subjects completed one page (approx. 15 items) of the EORTC QLQ-C30 between each mode as a distractor. Item scores by mode were compared using intraclass correlation coefficients (ICC); differences in scores within the 3-mode crossover design were evaluated with mixed-effects models. Difficulties with each mode experienced by participants were also assessed. RESULTS: 103 (92 %) completed questionnaires by all three modes. The median ICC comparing tablet vs IVRS was 0.78 (range 0.55-0.90); tablet vs paper: 0.81 (0.62-0.96); IVRS vs paper: 0.78 (0.60-0.91); 89 % of ICCs were ≥0.70. Item-level mean differences by mode were small (medians [ranges] for tablet vs. IVRS = -0.04 [-0.16-0.22]; tablet vs paper = -0.02 [-0.11-0.14]; IVRS vs paper = 0.02 [-0.07-0.19]), and 57/81 (70 %) items had bootstrapped 95 % CI around the effect sizes within +/-0.20. The median time to complete the questionnaire by tablet was 3.4 min; IVRS: 5.8; paper: 4.0. The proportion of participants by mode who reported "no problems" responding to the questionnaire was 86 % tablet, 72 % IVRS, and 98 % paper. CONCLUSIONS: Mode equivalence of items was moderate to high, and comparable to test-retest reliability (median ICC = 0.80). Each mode was acceptable to a majority of respondents. Although the study was powered to detect moderate or larger discrepancies between modes, the observed ICCs and very small mean differences between modes provide evidence to support study designs that are responsive to patient or investigator preference for mode of administration, and justify comparison of results and pooled analyses across studies that employ different PRO-CTCAE modes of administration. TRIAL REGISTRATION: NCT Clinicaltrials.gov identifier: NCT02158637.