Background: We studied quality of life (QOL), anxiety, and depression in patients with differentiated thyroid cancer (DTC) either during treatment with levothyroxine or during withdrawal from levothyroxine when whole-body scanning (WBS) needed to be performed. Methods: DTC patients projected to undergo WBS were included in the study. They were studied at two time-points – the day before levothyroxine withdrawal, and one month after levothyroxine withdrawal. They were asked to fill WHOQOL-Bref, BDI-II, and HADS questionnaires at both time-points, and blood samples were taken to measure TSH, Tg, and TgAb levels. Results: Twenty-nine subjects (11 males) with a mean age of 42.6 ± 14.1 years entered the study. From the first to second time-point, the mean TSH level increased from 0.73 to 106.9 U/ml and the mean Tg level increased from 20.4 to 63.6 ng/ml. QOL scores decreased in four dimensions (physical health: 67.8 to 25.7; psychological: 58.9 to 38.9; social relationship: 67.5 to 56; and environment: 57.2 to 48.8). Patients also felt more depressed (48.3% to 93.2%) and anxious (65.5% to 89.6%). All changes were statistically significant (p < 0.005). Conclusion: We found decreased QOL after short-term hypothyroidism, especially in physical health and psychological dimensions. We also found that patients became significantly depressed and anxious after levothyroxine withdrawal. Our findings suggest that alternative therapies, such as those employing rhTSH, should be considered for these patients. Psycho-oncological support might also be useful in helping them overcome their symptoms during short-term hypothyroidism; however, considering the reversibility of their symptoms, supportive care might be more effective.