Under the workers' comp law, (MGL c. 152 § 41) for injuries on or after January 1, 1986, a claim must be filed with the insurer within 4 years of the date you become aware of a connection between your injury or illness and your employment. In the case of the death of an worker, the claim must be within 4 years of the date of death. If you receive a Form 104 - Insurer's Notification of Denial , you have 4 years from the date you received the denial to appeal the it. For injuries prior to 1/1/86, the statute of limitations is 1 year, regardless of the employee's knowledge of the connection between your injury and/or illness and your work, although it is the burden of the insurer to show prejudice by the employee's failure to file within 1 year of injury.