Objective <p>This descriptive and cross-sectional study was conducted to determine the effect of taste alteration on malnutrition and quality of life in patients undergoing outpatient chemotherapy.</p> Materials and methods <p>The sample consisted of 330 patients who underwent chemotherapy in the outpatient chemotherapy unit of a university hospital between March and May 2023. Data were collected through face-to-face interview technique using the “Descriptive Characteristics Form”, “Chemotherapy-Induced Taste Alteration Scale (CI-TAS)”, “Malnutrition Universal Screening Tool (MUST)” and “World Health Organisation Quality of Life Questionnaire (WHOQOL-Tr 8)”. Independent samples <i>t</i>-test to compare two groups in normally distributed measurements and analysis of variance (ANOVA) to compare more than two groups (as advanced analysis; least significant difference (LSD) (in cases where the variances are homogeneous), Dunnet C when it was not homogeneous) were used. Pearson correlation analysis and regression analysis were used in correlational inferences.</p> Findings <p>It was found that 67.6% of the patients experienced a change in taste. The CI-TAS and WHOQOL-Tr 8 total mean scores of the patients were 2.45 ± 1.17 and 26.01 ± 5.75, respectively, and 21.8% of them were included in the moderate risk group for malnutrition. A significant correlation was found between CI-TAS and MUST and WHOQOL-Tr 8, and CI-TAS had a predictive effect on MUST and WHOQOL-Tr 8 (<i>R</i>²_adjusted = 0.014, <i>R</i>²_adjusted = 0.105).</p> Conclusion <p>As the severity of taste alteration intensified in patients, the risk of malnutrition rose, and their quality of life diminished. Consequently, taste alteration is an essential symptom that affects malnutrition and quality of life.</p>