Marguerite Tomany, 61, of North Grosvenordale, Conn., died from injuries suffered during the lightning strike.
The second woman, a 69-yea-old from Concord, Mass., remains in critical condition at Massachusetts General Hospital.
Rescue crews responded to Crane Beach Saturday around 4 p.m. after two women were struck by lightning.
Lifeguards were performing CPR to the women when rescue crews arrived.
An initial investigation shows that the women were in the water when the lightning struck as a storm popped up quickly.
The women had no pulse when rescue workers arrived on scene and were taken to Beverly Hospital.
Before arrival at the hospital, each woman had a pulse restored.
The patients were then taken to Massachusetts General Hospital in Boston.