Research was conducted to evaluate the vitality of Chrysanthemum segetum seeds from the herbarium collection of the Botany and Genetics Institute of the Pomeranian Academy in Słupsk. The oldest plants from the collection were more than 100 years old. The research material were unsplits dating from the years: 1895, 1922, 1923, 1967, 1971, 1977, 1980, 1998, 2000, 2005 and 2006. The unsplits from 2006 were collected from field. Seed germination was carried out in Petri dishes. In the first series there were three variations of temperature (5°, 20° and 30°C), treated as three repetitions. In the second series the seeds were germinated only at 20°C at three sowing dates. For the oldest seeds from the years: 1895, 1922 and 1923 only 15 seeds were sown in each repetition, because of their limited number. 100 seeds were sown for the remaining years. The Petri dishes were placed on a laboratory table, at a room temperature, in daylight. The observation of the germination of the seeds was conducted daily for 14 days. In the first series the seeds germinated at 20°C. In the second series the seeds germinated at all dates and in all repetitions and the germinating power fluctuated from 1.7% for the year 1977, to 22.2% for the year 1895. The differences in the number of the germinated seeds in all repetitions were insignificant. The biggest vitality was observed for the seeds from 1895. This means that Chrysanthemum segetum seed viability is at least 102 years. Longevity of a part of the seeds might result from the fact that they were kept in herbarium conditions (dry), because in damp soil they would have germinated earlier or they would have been affected by a fungus.