The generation of massive amounts of data in different forms (such as activity logs and sensor measurements) has increased the need for novel data mining algorithms, which are capable of building accurate models efficiently and in a distributed fashion. In recent years, several researchers proposed novel approaches to distribute the workload among several machines for classical clustering, classification and regression tasks [1]. However, only a few of them tackle the specific problem of density-based clustering. This problem has received much attention in the last decades, because of many desirable properties of the extracted clusters (arbitrarily-shaped, noise-free, robustness to outliers) which turn out the be useful in many application domains (e.g., spatial data analysis). Starting from the seminal work of DBSCAN [2], many algorithms have been proposed, but only a few of them are distributed. Unfortunately, existing distributed methods for density-based clustering suffer from several limitations. In particular, they are limited to data organized in a specific structure (e.g., they can analyze only low-dimensional feature spaces), or they suffer from overhead and scalability issues when the number of instances and attributes increase considerably [3-5]. These limitations depend from the