Purpose: There is scant information on the prevalence of pre-operative anemia in patients undergoing transcatheter aortic valve implantation (TAVI) and whether it is an independent predictor of mortality. We sought to determine the prevalence of pre-operative anemia and the effects of the various levels of pre-operative hemoglobin (Hb) on short- and long-term mortality in patients undergoing TAVI. Methods: 10-center observational study encompassing 1599 patients with aortic stenosis who underwent TAVI. Pre-operative anemia was defined by the World Health Organization criteria (Hb <12.0 in women and <13.0 g/dL in men). Uni- and multivariable analyses were performed to assess the association between preoperative anemia and various Hb levels, and all-cause mortality (30 days, 1 year median follow-up). Results: The prevalence of preoperative anemia was 57% with a mean pre-operative Hb concentration of 12.1±1.7 g/dL. Independent determinants of preoperative anemia were the following dichotomous patient-related variables (descending order of OR [95% CI]): pre-operative mitral regurgitation grade ≥III (1.80 [1.28-2.52]), history of heart failure (1.74 [1.41-2.16]), diabetes (1.47 [1.14-1.88]), male gender (1.46 [1.16-1.85]) and peripheral vascular disease (1.36 [1.07-1.73]). Body mass index was inversely associated with preoperative anemia (0.29 [0.16-0.51]). Postoperative aortic regurgitation grade ≥III was the most dominant (OR [95% CI]) independent predictor of 30-day mortality (4.64 [1.89-11.43]) while preoperative anemia was associated with an OR (95% CI) of 1.89 (1.04-3.46). Yet, the severity of preoperative anemia was the strongest independent predictor of mortality during follow-up; HR (95% CI) was 2.38 (1.37-4.13) in patients with Hb 10-11 g/dl and 2.92 (1.66-5.13) in patients with Hb <10 g/dl. Patients with anemia received 2 times more often ≥1 blood transfusion in comparison to patients without anemia. Blood transfusion independently predicted mortality at 30 days and follow-up; per unit of transfusion the risk of death increased by 20% (95% CI: 4-39%) at 30 days and with 13% (95% CI: 6-21%) during follow-up. Conclusions: Preoperative anemia is prevalent in more than 50% of patients undergoing TAVI. Notwithstanding differences in baseline characteristics, preoperative anemia independently predicted 30-day and late mortality. The need for blood transfusion was associated with worse outcome.