Shirley Harrison, 47, had pleaded guilty at an earlier hearing at Luton Crown Court to 29 charges of obtaining money by deception and eight charges of false accounting between March 1997 and December 2000.
Harrison of St James' Park Road, Northampton, committed the offences while working as a litigation clerk in Luton.
Her offences were described by Detective Constable Tony Bandy, of Bedfordshire Police's fraud squad, as "like stealing from the dead".
Relatives' complaints
She had been warned at the hearing in November by Judge Marie Catterson to expect jail.
The court heard she had diverted £443,919 over a five-year period.
The fraud came to light when relatives, who believed they had not received the full amount of an estate, complained to the Law Society.
Police then contacted beneficiaries from 35 other estates who made complaints and were compensated from the Solicitor's Indemnity Fund.
The court heard none of the money had been recovered.
Harrison's defence counsel said she had been suffering from a depressive illness at the time of the offences.
Sentencing her Judge John Slack said: "This was a serious breach of trust.
"In reality there is no justification for persistent fraud on your own clients."
He said he accepted mitigation put forward by her barrister, Charles Bott, that part of the money had been used to cover running expenses for the office.
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