Prior studies have proposed the unfavourable roles of diabetes mellitus (DM) in surgical populations. For patients who underwent transcatheter aortic valve implantation, the prognostic value of DM remains controversial. This review summarizes the effects of DM on short-term, mid-term and long-term prognosis in patients who undergo transcatheter aortic valve implantation. We searched the PubMed database to identify eligible articles. The odds ratio and hazard ratio with the corresponding 95% confidence interval were adopted for synthesizing short-term and medium- to long-term survival outcomes, respectively. The heterogeneity level and publication bias between studies were also estimated. Finally, 20 observational studies enrolling 19 260 patients met the eligibility criteria and, thus, were included in this review. An overall analysis identified that DM was significantly associated with the poor medium- to long-term overall survival (hazard ratio 1.21, 95% confidence interval 1.03-1.41; P = 0.019). However, no significant impact of DM on 30-day mortality was observed (odds ratio 1.10, 95% confidence interval 0.86-1.41; P = 0.46) in patients undergoing transcatheter aortic valve implantation. Further subgroup analyses indicated that the prognostic value of DM for medium- to long-term overall survival remained significant in the subgroups of multivariable origins of incorporated data, duration of follow-ups (1-year/≥2-year follow-up), Western populations and insulin-dependent diabetes mellitus. This meta-analysis demonstrates that DM is a strongly independent predictor for poor medium- to long-term overall survival but shows no significant effect of DM on 30-day mortality. Our findings need to be further verified and modified by more worldwide studies.