Ever since global markets developed from sellers to buyers markets companies have tried to integrate customers' knowledge into their innovations. User Innovation represents a new approach in which customers are actively integrated into the product innovation process. This quantitative study shows customers' attitudes towards User Innovation on three different levels - cognitive (What do customers know about User Innovation?), affective (What are customers' emotions and feelings towards User Innovation?) and behavioural (How likely are customers to participate within a User Innovation activity in the future?). Additionally, data from customers who have already participated in a User Innovation activity was compared to data from customers who have not participated yet. The results offer valuable clues on how to work with each customer segment effectively. 280 people filled out the online questionnaire and 220 of them fitted the target group.