Concomitant use of acetylcholine esterase inhibitors (AChEIs) and anticholinergic drugs, such as urinary antispasmodics (UA), is generally considered as inappropriate because of their opposite pharmacological actions. However, prevalence and the duration or factors associated with concomitant use have not been previously studied among community-dwelling persons with Alzheimer disease (AD). The aim of this study was to examine the prevalence and duration of concomitant use of AChEIs and UAs among community-dwelling persons with AD and factors associated with concomitant use. Register-based data of the MEDALZ-2005 Study included all community-dwelling persons with clinically diagnosed AD at the end of year 2005 in Finland. Persons using AChEI drugs during the 4-year follow-up (2006-2009) were included in the present study (n = 20,442). Among AChEI users, 1576 persons used UA during the follow-up. Prevalence of concomitant use of AChEIs and UAs was 7.3% (n = 1491) during the 4-year follow-up. The median duration of concomitant use was 236 days. Factors associated with concomitant use were age younger than 80 years (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.08-1.34), male sex (OR, 1.16; 95% CI, 1.04-1.30), Parkinson disease (OR, 1.98; 95% CI, 1.55-2.52), diabetes (OR, 1.25; 95% CI, 1.08-1.45), and prostatic cancer (OR, 1.54; 95% CI, 1.13-2.09). Despite their antagonizing action, concomitant use of AChEIs and UAs was quite common among Finnish community-dwelling persons with AD. In addition, duration of concomitant use was comparatively long. It is recommended to consider some other options than UAs to treat urinary incontinence among persons with AD.