To mark Remembrance Sunday, the family history website are offering free access to their UK wartime records until 23.59 GMT on Sunday 8 November.
To access the records, you need to register for a free account.
Subscriptions to Ancestry’s UK and Ireland records normally start at £13.99 per month.
One of the most important free record sets is the 1939 Register.
The register was a census of the civilian population of England and Wales – around 40 million people – taken on 29 September 1939, to help the government issue ID cards at the start of the Second World War.
It is the most recent census record or equivalent publicly available.
In addition, Ancestry’s First World War Service Records collection is also free to search.
This consists of the surviving service records of non-commissioned officers and other ranks who served in the British Army.
It includes attestation forms, which were completed by the individual when they enlisted; medical history forms; casualty forms; disability statements; regimental conduct sheets; awards; and proceedings on discharge.
Other free record collections include Civil Gallantry Awards, which were awarded to members of the Civil Defence Volunteers for bravery; the First World War Medal Rolls Index; and lists of First World War prisoners of war.
Rosemary Collins is the staff writer of Who Do You Think You Are? Magazine