The main goal of the master's thesis was to research the processing and merging of point clouds from mobile (MLS) and airborne laser scanning (ALS). By merging MLS and ALS point clouds, we obtain more information about the scanned environment and avoid certain limitations of each system. The merged point cloud covers the entire scanned surface except for atriums, which cannot be reached by either of the systems. Initially, we explored various options for registration of MLS point clouds in the Terrasolid software and determined the best process based on deviations at control points in a test area. We then added ALS point clouds to the MLS point cloud to obtain the merged point cloud. We did not find an appropriate program for automatic building modeling from the merged MLS and ALS point cloud on the market, so we used Terrasolid to automatically create building models only from the ALS point cloud. We manually created the model of a selected complex building from the merged point cloud and compared its accuracy and detail with the automatically created model. Finally, in the form of a discussion, we summarized the problems with data acquisition and processing, merging MLS and ALS point clouds, and building modeling.