The relationship between developers and designers is an important factor for successful User-Centred Design (UCD) work in an Agile Software Development (ASD) process. However, the determinants and long-term barriers for successful ASD in this relationship are still unclear. We asked designers and developers in an online survey about their roles, perceived level of ASD implementation, satisfaction with ASD, teamwork satisfaction, and perceived quality of communication and collaboration with the other role. Developers rated the main factors for successful ASD work as having access to designers and an optimal environmental setup. Designers’ main concern was related to improving wider teamwork, in particular sharing of information. A qualitative analysis of respondents’ comments confirmed these results broadly, and indicated that close cooperation and informal communication between designers and developers was desired. Respondents also perceived senior stakeholders’ hierarchical decision-making process as a barrier to successful ASD. Co-location and pairing of designers and developers was therefore also seen as an opportunity to enhance more localised and autonomous decisionmaking.