As business centers offer shared workspaces and facilities to multiple organizations, it is expected that these organizations interact more frequently with each other. More empirical research is needed on where these interactions take place in business centers and how this behavior is influenced. Therefore, the aim of this study is to analyze the location choice for face-to-face interactions of business center users. Data collected by means of a questionnaire and an Experience Sampling Method (ESM), was analyzed using a Mixed Multinomial Logit Model (MMNL). Results showed that inter-organizational interactions take place less frequently at workspaces or formal meeting spaces and more frequently at shared spaces such as the coffee corner, café/restaurant/canteen or at other informal spaces. These interactions are also more likely to be influenced by features of the physical work environment, as these interactions were found to be mainly coincidental compared to the intra-organizational interactions. These findings could help office designers with regard to stimulating face-to-face interactions among organizations in business centers.