Highly skilled professionals are regarded as one of the main driver for the economic development of cities through their effect on innovative capabilities. Skilled individuals are mobile in space and tend to cluster within a limited number of urban areas, therefore a crucial question is what factors shape this flows and influence the divergent levels of economic development across urban areas. Building on these considerations, this paper takes advantage of a large-scale dataset to shed light on the patterns and determinants of inventors' mobility across European urban areas. First, a descriptive analysis is carried out to document the dynamics of inventors' mobility and their spatial dimension. Second, a gravity model is used to analyse how job opportunities and socio-professional networks influence the flows of inventors between urban areas. From a methodological perspective, this paper uses a spatial filtering variant of the Poisson gravity model, which accommodate the nature of the data, while controlling for multilateral resistance and spatial autocorrelation in mobility flows. The descriptive analysis suggest that inventors' mobility occurs primarily between relatively large and collocated urban areas, partly because of the high level of circular and intra-firm mobility. The econometric analysis shows that employment opportunities, social networks, as well as various forms of proximity are important determinants of inventors' mobility.