Background: Identifying whether acute stroke patients are at risk of cognitive decline could improve prognostic discussions and management. Structural computed tomography (CT) neuroimaging is routine in acute stroke, and may, identify those at risk of post-stroke dementia (PSD) or post-stroke cognitive impairment (PSCI). Aim: To systematically review the literature to identify which stroke or pre-stroke features on brain CT scans, performed at the time of stroke, are associated with PSD or PSCI. Summary of review: We searched electronic databases to December 2020. We included studies reporting acute stroke brain CT, and later diagnosis of a cognitive syndrome. We created summary estimates of size of unadjusted association between CT features and cognition. Of 9536 citations, twenty-eight studies (41 papers) were eligible (N=7078, mean age 59.8-78.6 years). Cognitive outcomes were PSD (10 studies), PSCI (17 studies), and one study analysed both. Fifteen studies (N=2952) reported data suitable for meta-analyses. White matter lesions (WML) (6 studies, N=1054, OR=2.46, 95% CI=1.25-4.84), cerebral atrophy (4 studies, N=558, OR=2.80, 95% CI=1.21-6.51), and pre-existing stroke lesions (3 studies, N=352, OR=2.38, 95% CI=1.06-5.32) were associated with PSD. WML (4 studies, N=473, OR=3.46, 95% CI=2.17-5.52) were associated with PSCI. Other CT features were either not associated with cognitive outcome, or there were insufficient data. Conclusions: Cognitive impairment following stroke is of great concern to patients and carers. Features seen on visual assessment of acute stroke CT brain scans are strongly associated with cognitive outcomes. Clinicians should consider when and how this information should be discussed with stroke survivors.