Biosimilar medicines are defined as biological products highly similar to an already licensed biological product (RP). The market entry of biosimilars is expected to reduce the costs of biological treatments. This study aims to evaluate the range of differences between the prices of biosimilars and the corresponding RP for biologicals approved in four countries. This is a cross-national comparison of pricing of biosimilars in Argentina, Australia, Brazil, and Italy. The study examined online price databases provided by the national authorities of the investigated countries. Biosimilar price difference was calculated by subtracting the unit price of the biosimilar by the unit price of the RP, and then dividing it by the unit price of the RP. The results were presented as percentage. Brazil had the highest median price reduction (-36.3%) in biosimilars price, followed by Italy (- 20.0%) and Argentina (- 18.6%). All the biosimilars in Italy were priced below the RP presenting a minimum reduction of 6.3%, while in Australia, most of the prices of biosimilars were equal to the RP. In Argentina, one infliximab-biosimilar displayed price above the RP (40.7%) while the lower priced brand had a reduction of 14.4%. Brazil had four biosimilars with prices above the respective RP, including isophane insulin (1), insulin glargine (1) and somatropin (2). The study revealed a marked dispersion in the price's differences between biosimilars and RP across the studied countries. Governments should evaluate whether their policies have been successful in improving affordability of biological therapies.