Parkinson's disease (PD) patients develop progressive cognitive decline. The degree to which such decline impacts instrumental activities of daily living (IADL) among individuals in the early stages of PD without dementia is not well documented. The Everyday Cognitive Battery Reasoning subtest (ECB) was used to assess ability to solve everyday reasoning tasks for IADL among 19 non‐demented older adults with PD in comparison to 20 older adults without PD. The two groups were similar in age, education, race and gender. Individuals with PD had significantly lower scores (M = 61.98, SD = 12.03) than the comparison group (M = 69.80, SD = 9.48). Individuals with PD, who do not have dementia, may be more likely to experience difficulties in IADL requiring reasoning including medication use, finances, and nutrition. Even more serious implications lie in the capacity to make treatment choices.