For the analysis of geospatial data, the statistical spatio-temporal aggregation (SSTA) is a frequently used functionality. Possible applications include infor- mation extraction (Andrienko & Andrienko 2006), data fusion (Wiemann & Ber- nard 2010), generalization and schema transformation (Foerster et al. 2010). On the basis of spatial and temporal references, SSTA transfers thematic attribute values into a coarser spatio-temporal resolution using descriptive statistical op- erations. Reusable processing functions are increasingly offered in Spatial Data Infra- structures (SDI) through standardized interfaces using mainstream network tech- nologies. Due to the variety of use cases, a Web service for SSTA has a high po- tential for reuse. However, offering functionalities for geoprocessing within an SDI raises some challenges. They are concerning the aggregation process itself as well as the encapsulation of the aggregation functionalities in an SDI. This paper addresses these challenges by developing a generic framework for SSTA within an SDI. The components of the framework were realized by the use of several open- source software products. Following a modular approach, the communication between those loosely-coupled components is enabled through open, standardized interfaces. The result of the proposed work is a framework that enables users to easily perform a statistical ad-hoc aggregation of distributed spatio-temporal data.