Aim/background Measure Yourself Medical Outcome Profile 2 (MYMOP2) and Measure Yourself Concerns and Wellbeing (MyCaW) are two questionnaires that allow patients to define symptoms and concerns that are important to them. As the equivalence between the electronic and paper versions has not been assessed, we aimed to determine the measurement equivalence of electronic and paper versions of MYMOP2 and MYCaW among a group of adult patients treated for colorectal or anal cancer. We also aimed to investigate the patients' experiences of filling out the questionnaires. Methods A mixed methods approach was chosen to investigate measurement equivalence and to ensure a thorough investigation of the patients' experiences. The intra-rater reliability for ordinal data was assessed using the Intraclass Correlation Coefficient (ICC) and median difference. Agreement in descriptive data was assessed by two researchers independently. To capture the patients' experiences, we conducted semi-structured interviews over the phone. Interviews were transcribed verbatim and analyzed with content analysis. Results were presented as themes. Results A total of 30 patients were enrolled consecutively from a sequelae center treating patients after colorectal or anal cancer. Of these, 19 patients were also interviewed. The patients filled out MYMOP2 and MYCaW electronically and on paper. The intra-rater reliability for ordinal data was either excellent (n=11) or good (n=3) with ICCs ranging from 0.85 to 1. The median difference between ordinal data from electronic and paper versions was 0 (range -4 to 4). The agreement between the electronic and paper versions in the descriptive data ranged from 70% to 97%, with three-quarters being over 80%. Three themes emerged from the interviews: personal preferences, the importance of setup, and the availability of the questionnaires. Most patients preferred electronic versions as the advantages of electronic questionnaires outweighed the paper versions. Conclusion We found good intra-rater reliability and agreement in MYMOP2 and MYCaW questionnaires, demonstrating a high measurement equivalence. The interviews provided perspectives on the user experience and showed a preference for the electronic questionnaires as they had more advantages such as availability.