OBJECTIVES: Monoclonal antibodies (MAB) are biomedicines used for treatment of cancer, rheumatoid arthritis, psoriasis and inflammatory intestinal diseases. Since the first market entry in 1996 in Finland, their sales have increased continuously. We describe the penetration of MABs onto the Finnish pharmaceutical market in 1996­–2009. METHODS: The sales of MABs (wholesale figures in million euros, € M) with marketing authorisation were extracted by calendar year from the market database SLD Pharma (Finnish Pharmaceutical Data Ltd.) based on active substances. Annual figures were converted into 2009 values with the annually-updated Finnish National Pensions index (Social Insurance Institution). RESULTS: In 2009, the sales of the 17 MABs were €109 M or 5.6% of the total pharmaceutical market value (€1900 M). On the hospital market (73% of MAB sales in 2009), however, the respective share was 16% following a steady increase in 1999–2009. Up to the end of 2009, the overall cumulative MAB sales exceeded €479 M. Infliximab showed the highest cumulative sales of €120 M (entry in 1999). Adalimumab penetrated the market even more rapidly, with cumulative sales of €109 M (entry in 2003), and became the most-sold active substance in 2009 in Finland. The third MAB exceeding cumulative sales of €100 M was rituximab (entry in 1998). In terms of first-year sales, adalimumab was the most successful MAB, amounting to over €6 M. Bevacizumab achieved the second-highest first-year sales (€1.8 M in 2005), while the third MAB exceeding €1 M sales was ranibizumab (€1.7 M in 2007).  CONCLUSIONS: The penetration of several MABs onto the Finnish pharmaceutical market has been very successful within a short period of time.