The aim of this study was to examine the factor structure and the validity of the Finnish version of the 20-item Toronto Alexithymia Scale (TAS-20). As part of the Northern Finland 1966 Birth Cohort Project, the TAS-20 was presented to a sample of 5034 31-year old persons. A confirmatory factor analysis showed that the three-factor model, earlier established with the original TAS-20, was in agreement with the Finnish version of the scale. Three criteria of goodness-of-fit met the standards for adequacy of fit. For the total scale, internal reliability (Cronbach's alpha) was 0.83 and for the three subscales (factors 1, 2, and 3) it was 0.81, 0.77, and 0.66, respectively. Two- and one-factor models for TAS-20 were also examined, but the other models did not perform as well as the three-factor model. The factor model also worked well with a sample of 516 students with a mean age of 24.8 years. In conclusion, the TAS-20 scale is useful in the Finnish version, too.