Background Compared to participation rates among general populations, participation of people with chronic illness in the labour market lags behind. This is undesirable, both from the perspective of individuals’ well-being as from a macro-economic perspective for western countries where concerns exist about labour supply and sustainability of social security in the near future. To help develop successful policy measures to prevent early drop-out and support reintegration, we aimed to gain insight into the role of three age related characteristics that may relate to labour participation chances of people with chronic illness: the duration of their illness, how old they were when the chronic disease was diagnosed and the historical year in which the diagnosis was established. Methods We analyzed data of one (first) measurement of several cohorts of people diagnosed with a somatic chronic disease, who (had) participated in the Dutch ‘National Panel of people with Chronic illness or Disability’ since 1998 (N = 4634 in total). Multi-level logistic regression analyses were conducted to estimate random effects of the age at diagnosis and the year of diagnosis and fixed effects of illness duration on labour participation, while correcting for the effects of socio-demographic and disease characteristics and socio-economic indicators. Results A significant part of the variation in labour participation among people with chronic illness relates to the age they had when they were diagnosed. Furthermore, a longer illness duration is significantly associated with a lower chance of being economically active. This is more the case for men than for women. Labour participation of cancer survivors depends on the phase of the illness they find themselves in. No evidence was found that the year in which the diagnosis was established matters for employment chances later in life. Conclusion Age at diagnosis and illness duration relate to chronically ill people’s chances to participate in the labour market, but how and how strong they ...