Cognitive impairment is common in persons with cardiovascular disease (CVD). Cardiac rehabilitation (CR) improves many aspects of CVD linked to cognitive impairment. The current study explored whether CR may improve cognitive function. Potential mechanisms for cognitive changes were also examined through exploratory analyses, including changes in cardiovascular fitness and cerebral blood flow. Fifty-one older adults with CVD underwent neuropsychological assessment at baseline and discharge from a 12-week CR program. Cardiovascular fitness (i.e., metabolic equivalents [METs]) was estimated from a symptom-limited volitional stress test. Transcranial doppler quantified mean cerebral blood flow velocity and pulsatility indexes for the middle cerebral artery and anterior cerebral artery (ACA). Repeated measures ANOVA showed improvements in global cognition, attention-executive-psychomotor function, and memory. Exploratory analyses revealed improvement in METs and changes in ACA flow velocity, but only improvement in METs was related to improved verbal recall. CVD patients exhibited improvements in multiple cognitive domains following a 12-week CR program, suggesting that cognitive impairment is modifiable in this population. Although other studies are needed to elucidate underlying mechanisms, exploratory analyses suggest that cognitive improvements may be better explained by physiological processes other than improved cardiovascular fitness and cerebral blood flow.