Background Patient-reported outcome measures (PROMs) in clinical practice have the potential to contribute to and support shared decision-making processes by giving voice to patient concerns during consultations. However, the perspectives of patients diagnosed with chronic hematologic cancer on the use of PROMs are unknown. Objective To describe how patients diagnosed with hematologic cancer experience participating in a randomized PROM intervention study, including initial invitation, completion of questionnaires, and outpatient clinic visits. Methods A qualitative conceptual framework guided the study, using Interpretive Description with a focused ethnographic approach to explore patient experiences with PROMs in applied practice. Analysis was inspired by Habermas' social theory of communicative action. Results The analysis revealed 3 predominant themes of patient experiences: that PROMs were "In the service of a good cause,""The questions are not really spot on,"and "PROMs are sometimes used for something,"that is, unknown to the patient. Conclusions The patients' experiences were dominated by the perspective of the healthcare system and by gratitude and imbalanced power relations. During completion of questionnaires, patients struggled to identify with items, and the questionnaires were associated with low content validity. When visiting the outpatient clinic, patients reported that doctors and nurses rarely discussed patients' PROMs. Implications for Practice This study contributes knowledge of patient experiences of the integration of PROMs in hematologic outpatient clinical practice. Findings can guide further research and improve future implementation of PROMs.