It's the first price increase since the online retailer introduced its Prime membership program in 2005. The company said it would probably raise the price in January.
The hike will apply to users when they renew their membership.
Amazon has spent heavily to grow its business and expand into new areas, from movie streaming to e-readers and groceries. Prime membership also includes two-day free shipping on many products.
In an e-mail Thursday to members, the Seattle company stressed that it has not raised the price on Prime in the 9 years since its launch, even though shipping costs have increased and it has added new services, such as video streaming.
Online retailer Amazon is under fire for its shipping fees.
Two lawsuits accuse Amazon of encouraging its vendors to raise prices to include shipping fees, when those items shipped for free.
The suits claim customers who were not Amazon prime members, often received lower prices for the same products.
One lawsuit wants Amazon to refund the $79 membership fee for all prime members.
Amazon hasn't commented on the issue.