Objective Efficient detection of neurocognitive disorders is a key diagnostic challenge. We explored how simple bedside tests of attention, vigilance and visuospatial function might assist in identifying delirium in hospitalized patients. Methods Performance on a battery of bedside cognitive tests was compared in elderly medical inpatients with DSM-IV delirium, dementia, comorbid delirium-dementia, and no neurocognitive disorder. Results 193 patients [mean age 79.9±7.3; 97 male] were assessed with delirium (n =45), dementia (n =33), comorbid delirium-dementia (n =65) and no neurocognitive disorder (NNCD) (n =50). The ability to meaningfully engage with the tests varied from 84% (Spatial Span Forwards) to 57% (Vigilance B test), and was especially problematic among the comorbid delirium-dementia group. The NNCD was distinguished from the delirium groups for most tests, and from the dementia group for the Vigilance B test and the Clock Drawing Test. The dementia group differed from delirium groups in respect of the Months Backward Test, Vigilance A and B tests, Global assessment of visuospatial ability and the Interlocking Pentagons Test. Overall, patients with delirium were best identified by three tests – the Months Backward Test, Vigilance A test and the Global Assessment of visuospatial function with failure to correctly complete any two of these predicting delirium status in 80% of cases. Conclusion Simple bedside tests of attention, vigilance and visuospatial ability can help to distinguish neurocognitive disorders, including delirium, from other presentations. There is a need to develop more accurate methods specifically designed to assess patients with neurocognitive disorder who are unable to engage with conventional tests.