The effects of a changing age distribution on Norwegian aggregate consumption are analysed in this dissertation. This is done by estimating a consumption function which controls for age structure effects. Both multivariate system and single-equation estimation methods are used, and the model is estimated on quarterly time series data from 1968(3) to 1998(4). The estimation results show that changes in the age structure of the population affect aggregate consumption significantly, and that the age structure impact is in line with economic theory. More specifically, the results support the Life Cycle Hypothesis, which predicts that young adults and old persons have a higher average propensity to consume than the middle-aged. Furthermore, the model is shown to encompass a consumption model which does not control for age composition effects. Compared to the consumption model of Eitrheim et al. (2000), who use the same data set but without an age structure variable on the same sample, the model has both lower equation standard error and more stable parameters over the estimation period. The model is, however, not well-specified for the 1980's.