Inadequate health literacy or numeracy and probable cognitive impairment influence patients' medical outcomes. The study purpose was to examine the prevalence of inadequate health literacy, inadequate health numeracy, and probable cognitive impairment among bariatric surgery candidates and examine associations with undergoing bariatric surgery. Patients (N = 314) completed measures assessing these constructs during a required pre-surgical psychological evaluation. Approximately 9.6%, 24.2%, and 29.5% of the sample had inadequate health literacy, inadequate health numeracy, and probable cognitive impairment, respectively. In univariate analyses, those with inadequate levels of health literacy, inadequate health numeracy, and probable cognitive impairment were less likely to undergo surgery. In a multivariate model, inadequate health literacy independently predicted a lower likelihood of undergoing bariatric surgery. Findings underscore the importance of assessing these factors.