Deutsche Telekom AG and United Internet AG say emails sent by their customers will be automatically encrypted starting Friday.
Initially the encryption will only be secure between customers of Deutsche Telekom's T-Online service and United Internet's GMX and WEB.DE services.
The companies claim these three providers account for two-thirds of primary email addresses in Germany.
Deutsche Telekom CEO Rene Obermann says the initiative came because "Germans are deeply unsettled by the latest reports on the potential interception of communication data" revealed by NSA leaker Edward Snowden.
It wasn't immediately clear if German security services would have a key to decrypt the emails.
Copyright 2013 The Associated Press.