The European Commission (EC) is the executive branch of the European Union operating as a cabinet government with 27 members ("commissioners"). It is responsible for proposing legislation, implementing decisions, upholding the EU treaties and managing the day-to-day operations of the EU.
Once legislation is passed by the European Council and Parliament, the EC is responsible for its implemented, which it does through the member states or its agencies. The Commission is also responsible for implementing the EU budget and ensuring that EU funds are spent correctly.
The EC's rules of procedure set out the commission's operation and organization.