Daily collaboration of senior doctors, residents and nurses involves a major potential for sharing knowledge between professionals. Therefore, more attention needs to be paid to informal learning to create strategies and appropriate conditions for enhancing and effectuating informal learning in the workplace. The aim of this study is to visualize and describe patterns of informal interprofessional learning relations among staff in complex care. Questionnaires with four network questions - recognized as indicators of informal learning in the clinical workplace - were handed out to intensive and medium care unit (ICU/MCU) staff members (N = 108), of which 77% were completed and returned. Data were analyzed using social network analysis and Mokken scale analysis. Densities, tie strength and reciprocity of the four networks created show MCU and ICU nurses as subgroups within the ward and reveal central but relatively one-sided relations of senior doctors with nurses and residents. Based on the analyses, we formulated a scale of intensity of informal learning relations that can be used to understand and stimulate informal interprofessional learning.