There is a higher incidence of vitamin D deficiency in older adults. This may play a plausible mechanistic role in the occurrence of increased adverse events after non-ST elevation acute coronary syndrome (NSTEACS). This study investigated whether total vitamin D levels at the time of presentation predicted adverse outcomes in older adults undergoing invasive management of NSTEACS. Of the 629 patients screened, 300 high-risk older adults with NSTEACS managed by an invasive strategy were recruited. Serum total 25-hydroxyvitamin D was measured at index presentation. The primary outcome was defined as 1-year composite of all-cause mortality, acute coronary syndrome (ACS), unplanned repeat revascularisation, significant bleeding or stroke. Mean age was 80.5±4.8 years (61.9% male). Median vitamin D level was 29.5nmol/L [interquartile range IQR 16.0-53.0 nmol/L] and was split equally by the median for analysis forming two groups: high (median vitamin D 53.0 nmol/L [IQR 40.0-75.0]) and low (16.0 nmol/L [11.0-23.0]). The primary outcome occurred in 76 patients (25.9%); 32 (21.9%) in the low group and 44 (29.9%) in the high group, p = 0.12. Multivariable analyses showed no significant difference in the primary composite outcome at 1 year between the low and high group of baseline serum vitamin D (Hazard Ratio 1.20 [95% Confidence Interval 0.72-2.0], p = 0.48). Serum total vitamin D, measured at the time of angiography, was not associated with adverse outcomes at one year in this high-risk older cohort of patients with NSTEACS undergoing invasive management.