Background Nausea seems underreported during pelvic radiotherapy. Objective The aims of this study were to investigate if a 5-week recall measure of nausea covering the entire radiotherapy period was comparable with accumulated daily nausea measurements and to investigate if the measuring method affected potential difference in quality of life (QoL) between nauseated patients and patients free from nausea. Methods This longitudinal methodology study covered 200 patients (mean age, 64 years; 84% women; 69% had gynecological cancer). The patients graded QoL (Functional Assessment of Cancer Therapy-General). They registered nausea daily and at a 5-week recall at the end of radiotherapy. Results The nausea-intensity category scale and visual analog scale correlated well (Spearman correlation coefficient = 0.622). According to the 5-week recall, 57 of 157 answering patients (36%) experienced nausea during the radiotherapy period. Using the daily nausea measurements, 94 of 157 patients (60%) experienced nausea (relative risk, 1.65; 95% confidence interval, 1.29-2.10). Of these 94 nauseated patients, 39 (42%) did not report nausea using the 5-week recall. The nauseated patients experienced worse QoL (physical/functional subscores) than patients free from nausea whether nausea was registered daily or at the 5-week recall. Conclusions Almost half, 42%, of the patients who experienced nausea according to daily nausea measurements did not report having had nausea according to the 5-week recall. Nauseated patients graded worse QoL than patients who were free from nausea. Implications for Practice Nursing professionals should measure nausea repeatedly to identify patients at risk of nausea and worsened QoL, to be able to deliver evidence-based antiemetic treatment strategies.