We recently reported an increase in prevalence and frequency of tension-type headache (TTH) over a 12-year period in the young Danish population. The aim of the present study was to analyse whether this increase was related to increased pain sensitivity. The study was a cross-sectional replicate of a large Danish population study. It compared 113 subjects aged 25-36 years in 2001, with 221 comparable subjects in 1989. Tenderness was considerably higher in 2001 than in 1989. When stratified according to presence of headache, the increase in tenderness was clinically and statistically significant only in women with frequent TTH. The pressure pain threshold was significantly lower in 2001 compared with 1989 in women with frequent TTH. The increase in tenderness in the population may predict an even higher prevalence of TTH in future. The changes support the hypothesis of central sensitization in TTH.