Sam Baldock's first goals in a West Ham shirt helped the Hammers move into second place in the Championship.
The former MK Dons man, who moved to Upton Park in the summer transfer window, scored twice in a frantic eight second-half minutes when three of the Hammers' four goals went in.
The home side were also ahead at the break thanks to an early John Carew header before Blackpool's defence let in three in eight minutes.
Baldock scored both the second and third from close range before Welsh midfielder Jack Collison made it four in the 55th minute.
Blackpool drop five places to 13th in the Championship while West Ham are just two points behind table-toppers Southampton.
