Mr Yanko Tsv. A. filed an application with the Bulgarian Patent Office (BPO) for the grant of a patent for an ‘Active solar heating system’. The BPO dismissed the application as the Expert Department of ‘Mechanical Engineering, Construction, Electronics and Electronical Engineering’ determined that the invention applied for was not industrially applicable and therefore not patentable. Mr Yanko Tsv. A. appealed the decision of the Expert Department before the ‘Department of Disputes’ of the BPO and then before the Court.