Oral mucositis (OM) is a frequent and potentially severe complication of cancer chemotherapy. The aim of this descriptive, cross-sectional study was to better understand patients' experiences and perceptions of chemotherapy-induced OM. Fifty-seven adult patients in a chemotherapy day unit who had completed at least 2 cycles of chemotherapy within the previous 12 months and who were receiving chemotherapy at the time of study completed the questionnaire (response rate, 86.3%). Results demonstrated that 75.4% of participants (N = 57) had experienced at least one episode of OM since their first chemotherapy. Dry lips were the most common symptom of OM (n = 20, 54.1% previously; n = 14, 73.7% currently). Ulcerated mucosa was regarded as the most significant problem caused by OM (n = 14, 87.5% previously; n = 8, 100% currently), whereas pain on swallowing was considered as the most distressing mucositis-related effect (n = 14, 87.5% previously; n = 4, 100% currently). The findings revealed a high incidence of chemotherapy-induced OM. Chemotherapy-related mouth problems were perceived as problematic and caused varying degrees of distress. A systematic oral assessment method can be used in future studies with a cohort of patients to further generalize the pattern of patients' experiences of OM.