The move allows users to make audio and video calls and send Skype instant messages via the website once they download a browser plug-in. UK-based customers are the first to be offered a "preview" version of the technology. Germany and the US will follow "in the coming weeks".
However, analysts questioned whether the effort would help Microsoft regain ground lost to Google's Gmail.
"With Skype for Outlook.com, you can choose the right medium for your message, whether it is an email, call, video call or instant message," Skype said in a blog post. "You can connect with your Skype and Messenger friends all in the same place."
Microsoft announced an overhaul of its webmail service in July 2012. The firm has begun shifting away from its Hotmail webmail brand - which it has used since acquiring the product in 1998 - by encouraging users to upgrade their accounts which are subsequently renamed Outlook.com.
It has also shut down its Windows Messenger chat tool in most countries and urged users to switch over to Skype.
Microsoft paid $8.5bn (£5.5bn) to acquire Skype in 2011, buying out eBay and the private investors who owned the service. It remains the Windows-maker's biggest ever takeover. Adding the service to Outlook.com may encourage users to use the webmail service.
Source: BBC News
