PurposeWe report here the first population-based incidence rates and prognosis of primary central nervous system lymphoma (PCNSL) in Finland. MethodsFinnish Cancer Registry data by histological diagnosis and tumor location (2007-2017) for cases with diffuse large B-cell lymphoma.ResultsDuring 2007–2017, 416 new cases of PCNSL were reported (202 males, 214 females). The average age-adjusted incidence in males vs. females for 2007-2009, 2010-2012, 2013-2015 and 2016-2017 was 0.57/100,000 vs. 0.48/100,000 person-years, 0.66/100,000 vs. 0.55/100,000, 0.53/100,000 vs. 0.63/100,000, and 0.76/100,000 vs. 0.66/100,000 respectively. The incidence was highest, 3.27/100,000, among people aged 75–79 years. From 2007–2012 to 2013–2017, the 2-year age-adjusted survival rate increased from 36% to 41%, and the 4-year survival rates from 31% to 37%. Among patients aged 70+ years, the corresponding 2-year survival rates were 25% and 29%, and the 4-year survival rates 25% and 22%.ConclusionAge-adjusted incidence of PCNSL increased from 0.57/100,000 (2007–2012) to 0.63/100,000 (2013–2017). The annual increase was 3.8% being among the highest reported in the world. The prognosis was poor, although a minor improvement in 4-year survival was found.