The dataset contains a time series of weekly incidence of general practitioner (GP) consultation by patients with influenza-like illness (ILI) in the Netherlands. The data was retrieved from the NIVEL Primary Care Database, Sentinel Practices. The catchment population of the sentinel GP network is approximately 1% of the entire Dutch population. The time series spans a period of 45 years, from January 5, 1970, to June 16, 2014, and is stratified into 10 age classes. In addition to weekly ILI incidence, the total catchment population size per age class is given as well. The data is used in our study about the estimation of age-specific susceptibility to influenza in the Netherlands, and its relation to loss of CD8+ T-cell memory.