The satellite broadcaster's EPG is used by more than 10m customers in the UK - including 4.22m Sky+ HD subscribers - to access live channels, video on-demand and a range of other services.
Sky said that all customers on average interact with the EPG more than 1.2 billion times every month, meaning its functionality is of key importance.
The new Sky Guide, which starts rolling out to set top boxes from today, brings a number of enhancements to make it easier for Sky+ HD customers to locate and discover new and favourite shows.
The guide has been upgraded to "pinpoint HD graphics", offering a "sharper and sleeker user interface", said Sky.
Navigation has been improved so that the number of channels featured on each page of the guide is increased from six to eight, making it easier to browse through the content.
In the Sky+ planner, new categorised recordings mean that Sky customers can browse through their stored programmes by genre for the first time. Content will be divided into categories such as entertainment, movies, sport, news, kids, music and documentaries.
Luke Bradley-Jones, Sky's brand director of TV Products, said that one of the "key changes" in the new guide is more closer integration of video on-demand content, following the success of Sky Anytime+, Sky's internet-delivered on-demand service that is now available in 5m homes.
New landing pages have been included for each different programme genres. Sky Movies customers, for example, can choose to access live movies, on-demand through Sky Anytime+ or their stored recordings from a single Sky Movies page.
"Hosting over 1.2 billion customer interactions each month, the Sky Guide is a fundamental part of the Sky experience, which is why we've worked hard on these new features to continue to give our customers the best experience we possibly can," said Bradley-Jones.
"We also want to make it as easy as possible for our customers to find the content they love, and we're confident that our new-look EPG does just that.
"The combination of world-class content, an enhanced EPG and innovative on-demand services like Sky Anytime+ means that our customers will soon be able to enjoy even more control and choice over their viewing experience."
Sky said that the new Sky Guide will roll out in a phased programme to all Sky+ HD boxes by the end of the year.
This started today with Sky+HD 890 and 895 boxes, and will subsequently move on to Pace, Samsung and Sky+HD 780 boxes later this year.
In a post on the Sky Views blog, Bradley-Jones said that new Sky Guide is also the first time that Sky subscribers have been involved in the development process, after a small group of customers was invited into a closed beta last month.
"This approach has proved to be a big success, since testing the functionality and features with such a highly-engaged group has identified a number of improvements that have since been incorporated into the new look. We're very grateful for the invaluable feedback," he said.
"What was also noticeable was how much these customers enjoyed playing a part in helping building this new product, and it's certainly something that we will be looking to repeat with other software trials."