Several studies have shown that malnutrition helps to predict the occurrence of adverse outcomes after transcatheter aortic valve replacement. However, there is still controversy and uncertainty regarding the prevalence and consequences of malnutrition. We performed a systematic review and meta-analysis to assess the relationship between malnutrition and poor postoperative outcomes in transcatheter aortic valve replacement. Observational studies were searched in PubMed, EMBASE, Cochrane Library, Web of Science, and MEDLINE regarding the relationship between malnutrition and adverse outcomes after transcatheter aortic valve replacement, with the primary end-point being all-cause mortality and secondary outcomes such as cardiovascular complications and readmission rates. This meta-analysis was registered in PROSPERO (number CRD42022310139). A total of 10 studies involving 5936 subjects were included in the systematic review and meta-analysis. The results showed that malnourished patients had an increased risk of all-cause mortality after transcatheter aortic valve replacement compared with non-malnourished patients (hazard ratios [HR] = 1.32, 95% CI [1.13, 1.53], P <.01). Subgroup analysis showed that in Asia, postoperative all-cause mortality was significantly higher in malnourished transcatheter aortic valve replacement patients than in non-malnourished transcatheter aortic valve replacement patients (P <.01), and in addition, sample size and follow-up time may have contributed to the large heterogeneity. Malnutrition increases the risk of all-cause mortality in such patients and may predict the occurrence of adverse postoperative outcomes.