Ancestry.co.uk have now made available the Freemasonry Membership Registers for England 1751-1921 and Ireland 1733-1923. Containing over 2 million records, they reveal details such as name, profession, birth year and other personal information. This now makes it now very easy discover if there were Freemasons in your family. These registers list men who belonged to the United Grand Lodge of England (UGLE).
If you are seeking members before 1751 and after 1921 then the Library and Museum of Freemasonry can carry out a search of the records for you (cost implication)
For further information of Freemasonry try the resources section of the Library and Museum of Freemasonry.
Also try searching the Masonic Periodicals Online