Background: in the field of rare diseases (RDs) most of the European studies on budget impact analysis of drugs that have been conducted often lay on theoretical assumptions and focus only on Orphan drugs (ODs). Objectives: we aimed to estimate the budget impact of specific drugs for non-oncological RDs, both ODs and non-ODs, using real-world data about patients residing in Veneto Region (Italy) and to describe its expenditure structure and dynamics. Methods: a population-based multi-source observational study was conducted using data from Regional administrative databases; an ad-hoc drugs’ list specific for RDs including both ODs and non-ODs and classifying them by ATC codes has been created. Results: In 2019, the total expenditure for drugs specific for RDs was EUR 97.2 million (6.6% of the total Regional budget). The RD drug list included 58 ATC codes, of which 15 ATC had an annual budget impact over EUR 1 million (“blockbuster drugs”). The most expensive treatment was a non-OD drug (Coagulation factor VIII). The two most represented therapeutical areas were the metabolic and the hematological ones. Conclusions: Cost analyses on RD high-cost drugs expenditure should consider any specific RD drug, not only ODs. Expenditure dynamics for RD drugs are peculiar showing “blockbuster drugs”. Some therapeutical areas seem to be lacking in the drug research field.