Besides a variety of dry grinding methods, wet grinding technology can be applied for poorly water-soluble active pharmaceutical ingredients (APIs). Agitated media mills are suitable for milling finest particles in any appropriate liquid even down to the nano-range. The issue of abrasion can be solved by the targeted combination of mill and bead material. Furthermore, optimization of the grinding parameters can reduce the required grinding energy as well as contamination of the products. To enable application of milling processes in the earliest stage of pharmaceutical R&D work, sample quantities need to be reduced to a few grams and processed with the highest possible recovery of the product. The small lab and research mills have to be designed analogously to the production machines to make scale-up and validation possible. The technology of pharmaceutical processing in general and agitated media mills in research, pilot, and production scale, test results for optimization of mill parameters and materials are presented and an insight into containment techniques is provided.