The by-election process has begun following the death of the former Welsh Government minister Carl Sargeant.
Mr Sargeant was found dead at his home in Connah's Quay two weeks ago.
As required by the Assembly's rules, the Presiding Officer, Elin Jones, has formally declared a vacancy in his Alyn and Deeside constituency.
Those same rules require that a by-election should be held within three months of the seat becoming vacant which means that a new Assembly Member must be chosen by February 7th 2018.
It's thought that a date set for a vote won't be set until after Mr Sargeant's funeral which will take place on December 1st.
The 49-year-old was found dead last Tuesday by his wife, four days after being removed from his role in the Welsh Government.
The inquest into the death of former Welsh government minister Carl Sargeant is due to open on Monday.
Former Special Adviser to Carwyn Jones claims ministers such as Carl Sargeant were 'undermined' in an atmosphere of "fear and loathing".