Objective The aim of this study is the evaluation of a novel cognitive test, the hard Test Your Memory (H‐TYM), in the detection of mild Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). Methods This paper uses a prospective study in an outpatient memory clinic. We recruited 97 patients with a diagnosis of mild AD or aMCI aged between 50 and 80 years. All scored 20 or more on the mini mental state examination (MMSE). We recruited 200 controls from a similar background. The patients were given a novel short cognitive test (H‐TYM) designed to test recall of newly learnt visual and verbal material together with the Addenbrooke's Cognitive Assessment Revised, MMSE, and TYM test. Results Alzheimer's disease/aMCI patients completed the H‐TYM with an average recall score of 6.69 (SD 3.45); control participants scored an average of 20.4 (SD 4.54). The H‐TYM detected 95% of cases of mild AD/aMCI on the basis of an optimum cutoff point. The area under the receiver operating characteristic for the H‐TYM ratio was calculated to be 0.989 with a 95% confidence interval of 0.980–0.997. Conclusions The H‐TYM test has an excellent ability to discriminate between AD/aMCI cases and healthy controls. The H‐TYM is a useful tool for the detection of mild AD/aMCI, and it detects AD/aMCI in the majority of patients who “pass” the MMSE and Addenbrooke's Cognitive Assessment Revised. Copyright © 2013 John Wiley & Sons, Ltd.