Situated in the Senedd building in Cardiff Bay, the Assembly consists of 60 Assembly Members (AMs) elected under a mixed member proportional representation system.
This means that each voter has two votes, one to elect a constituency representative and the other to choose a political party at regional level.
In all, 40 AMs are directly elected from single member constituencies equivalent to those used for the House of Commons, through a first past the post system.
The remaining 20 AMs are elected from five regional constituencies in order to provide a degree of proportionality within each region.
Elections to the Assembly take place every four years, most recently in 2011. This resulted in 30 Labour AMs, 14 Conservative AMs, 11 Plaid Cymru AMs, and 5 Liberal Democrat AMs. In order to avoid a clash with the UK general election in 2015, the current Assembly term has been extended to five years.
The next Assembly elections will take place in five years rather than the usual four.
With Labour holding exactly half of the seats in the Senedd, the party decided to govern alone for the fourth assembly with Carwyn Jones, leader of the party, as First Minister.
Without a working majority, Mr Jones was careful to leave open the possibility of forming a coalition government later in the term.
The First Minister chose seven Welsh ministers with responsibility for different policy areas. Together with the First Minister they form the cabinet.
He has also appointed three deputy ministers to support the work of particular ministers.
As the second largest party in the Assembly, the Conservatives continue their role as the main opposition.
The rest of the AMs are responsible for scrutinising decisions, policies and spending commitments of ministers.
This is done either during the plenary sessions or as part of a committee.
Plaid Cymru (11)
Liberal Democrat (5)
Opposition parties can also try to change government legislation or policy by putting forward amendments to motions tabled during a debate, but these rarely succeed because of the government's strength in the chamber.
The Assembly is chaired by the Presiding Officer - currently Rosemary Butler AM.
The Presiding Officer's main responsibility is chairing the plenary sessions and maintaining order in the chamber.
She is also responsible for ensuring that business is handled with equality and impartiality - and is viewed by many as a figurehead for the entire organisation.
The deputy Presiding Officer is the Conservative AM David Melding.
Salary and expenses
An AM's basic salary is currently £53,852 but they are also allowed to claim for their offices as well as other expenses.
However, following a number of expenses scandals in Cardiff Bay, an independent panel has
proposed drastic reductions
in the expenses AMs can claim.
Under the new rules, AMs can no longer claim mortgage interest on second homes but 25 of the 60 politicians can still rent accommodation near Cardiff Bay instead.
They cannot claim for furniture and fittings on second homes, there is no longer a food allowance and a receipt has to be provided for every claim.
AMs' expenses are now published on the
Members are also required to register any
which might be thought to influence their conduct or actions in the Assembly.