Background: The prevalence of lanolin sensitivity in referred patients is less than 4%. Objectives: To (1) describe patients with positive patch-test reactions to lanolin, (2) determine clinical and occupational relevance associated with reactions to lanolin and common sources, and (3) examine the frequency of co-reacting allergens. Methods: A retrospective analysis of 26,479 patients patch-tested by the North American Contact Dermatitis Group (NACDG), 1994 to 2006. Results: Overall, 2.5% of patients (643 of 25,811) tested to lanolin alcohol 30% in petrolatum had positive reactions. Prevalence decreased from 3.7% in 1996 to 1998 to 1.8% in 2005 to 2006 (p <.0001); 83.4% of all positive reactions were currently relevant, but only 2.5% were occupationally relevant. Lanolin-positive patients were 1.2 times more likely to be male and 1.4 times more likely to have a history of atopic dermatitis when compared to allergic, but lanolin-negative, patients (p < .0002 and p < .0001, respectively). Cosmetics were the most common source. Lanolin-positive patients were significantly more likely to be co-sensitized to another NACDG standard screening allergen (p <.0001). Conclusions: The prevalence of allergic patch-test reactions to lanolin in North America patch-test populations is decreasing. Current relevance of reactions was high, but occupational relevance was low. Concomitant reactions were more common in lanolin-positive patients.