Objective: A simple brief olfactory detection test, The Peanut Butter Test, has distinguished patients with Alzheimer's disease from those with mild cognitive impairment and other dementias. It measures if one can smell peanut butter with one nostril and then the other. Those with Alzheimer's disease have a stronger detection with their right nostril (17.4 cm) versus their left nostril (5.1 cm). Since half of adults with HIV experience HIV-associated neurocognitive disorder (HAND), such olfactory tests may be useful. Method: In three cases of older (50+) adults with HIV, we administered a neuropsychological battery (e.g., Trails B, Hopkins Verbal Learning Test), the Pennsylvania Smell Identification Test, the Smell Threshold Test, and two detection stimuli (i.e., cocoa, cinnamon) along with the Peanut Butter Test. These cases were free of any nasopharyngeal obstructions or other conditions that could impair olfaction. Results: Smell threshold and detection between nostrils were not noticeably different among these cases. However, two cases performed similarly on the neuropsychological measures (Trails B: 135 & 107 sec; Hopkins Delayed: 6 & 11 correct) and the smell identification test (both 30, 75% correct). The third case experienced much poorer smell identification (15, 37.5% correct) and experienced poorer neuropsychological performance (Trails B: 225 sec; Hopkins Delayed: 2 correct). Conclusion(s): This case study suggests that smell identification, rather than smell detection and threshold may be more germane in predicting neuropsychological functioning. Given some olfactory declines observed in HIV, perhaps this corresponds to select neural circuitry adjacent to or associated with HAND (i.e., fronto-striato-temporal circuitry).