The apportionment of seats within the European Parliament to each member state of the European Union is set out by the EU treaties. According to European Union treaties, the distribution of seats is "degressively proportional" to the population of the member states, with negotiations and agreements between member states playing a role. Thus the allocation of seats is not strictly proportional to the size of a state's population, nor does it reflect any other automatically triggered or fixed mathematical formula. The process can be compared to the composition of the electoral college used to elect the President of the United States of America in that, pro rata, the smaller state received more places in the electoral college than the more populous states.

The 1979 European Parliament election was a series of parliamentary elections held across all 9 European Community member states. They were the first European elections to be held, allowing citizens to elect 410 MEPs to the European Parliament, and also the first international election in history.