Myelodysplastic syndromes (MDS) are a diverse group of clonal hematopoietic stem cell diseases that may progress to acute myeloid leukemia. Here, we present incidence of myelodysplastic syndromes based on a nationwide, registry-based study. A total of 1906 MDS cases were reported to the Finnish Cancer Registry during 1997–2016. We analysed the age-standardized incidence rates using the new European standard population, incidence trend and changes in trend by sex, age group and calendar year using Poisson regression and joinpoint regression. The average age-standardized incidence rate was 3.92 per 100,000 person-years. The incidence of MDS increased in a linear-quadratic fashion across 10-year age groups and was higher among men (5.43 versus 3.14 per 100,000). The incidence trend increased during the first 15 years followed by a decline towards the end of the study period. A similar trend was found in subgroups by sex and age. Our results show a similar or slightly higher MDS incidence in Finland as in other Western countries, with an increasing trend, but some decrease in the end. The increasing incidence may reflect improved reporting and coding, or there could be a genuine increase in MDS over time.