Narrowband UVB (NB-UVB) phototherapy remains versatile, safe, and efficacious for multiple dermatologic conditions even with recent pharmacologic treatment advances. Polypharmacy contributes to prescribers pursuing phototherapy as a nonpharmacologic treatment, but some wonder if it is as effective and safe for older patients. This study aimed to determine if NB-UVB is equally effective in both older and younger adults treated with the same protocol and to examine the association between photosensitizing medications, clearance, and erythema rates in older vs younger adults.