There is no Middlesex County death window. The filing clerk is the city or town of death. The state Registry is slower statewide mail. Do not confuse Middlesex County, Massachusetts with Middlesex County, New Jersey.
Who may request
Follow mass.gov. Eligible requestors include next of kin and people with a direct tangible interest, at the registrar's or local clerk's discretion. Confirm on that page.
What to bring
Confirm current ID on mass.gov and on the city or town clerk page before you go.
Where to write or visit
Go to the city or town clerk of the place of death (Cambridge, Lowell, Newton, Somerville, Waltham, and the other Middlesex towns each keep their own books). Statewide: Massachusetts Registry of Vital Records and Statistics, per mass.gov.
Notes from the desk
State in-person copies are $20 each this check. Mail to the Registry is $32 per copy. Online or phone through VitalChek is $54 first and $42 each additional. City and town clerks often charge less (Cambridge lists $15). Confirm the clerk of the city of death. This desk takes no cut.