Question. If a widow remarries, are there any rules as to whether she uses her maiden name or married name as a surname on the marriage cert?

The basic answer to your question is that when a woman marries, her name changes to that of her husband. So if she is widowed and remarries, she will remarry under her first husband's surname.

It would be very, very, very unusual for a widow to revert to her maiden name. Are you sure the lady in question was actually married before? Does the marriage certificate give her as a widow, but with her surname matching that of her father?

IF this is in the uk then she should have both names on the certificate, and the index too.
The format is 'married name' formerly 'maiden name'
If this was a 4th marriage the format becomes 'last married name', lately 'previous married name' previously 'first married name' formerly 'maiden name'
Other countries do things differently.
Rob

Sorry to contradict, but marriage certificates do not provide former surnames (except to the extent that they give the name of the bride's father which is generally the same as her maiden name).

I think you are confusing marriage certificates with birth certificates which do provide all the previous surnames of the mother.

I see that the subject is not as clear cut as I'd hoped. I'm trying to trace a relative in the BMD records without resorting to marriage certs at this stage.
When Miss Dixon marries Mr Nolan, she'll become Mrs Nolan. When Mr Nolan dies and she remarries Mr Rogers will I see her name as Nolan Rogers in the BMD records?...or what?
Many thanks to you all, confused Alan.

Hi Alan

It's difficult for anyone to answer your question with any accuracy since you don't say where in the world the marriage takes place.

Should you be discussing England, see the BMD tutorial at http://home.clara.net/dixons/Certificates/marriages.htm