Beginning next week, developers will be required to include a rating for all new and updated games they add to the Android Market, Eric Chu, who works with Google's Android Developer Ecosystem, wrote in a blog post.
Developers will also have to rate their existing apps over the next few weeks. If they don't, the applications will be rated "mature," he wrote.
Applications will have one of four ratings: all, pre-teen, teen and mature.
Google is making the change in response to Android users asking for more information about applications, Chu said.
The move may also be a response to criticism that the Android Market is a source of porn. Google's policy is to allow any application in the market, and then remove any that are found to break its rules.
Apple CEO Steve Jobs has taken jabs at Google for the policy. Apple vets applications before adding them to the iPhone App Store. At the unveiling of iOS 4 in April, Jobs said Apple had no plans to open up the store, implying that accepting any application would turn it into a source of porn, like the Android market, and let anyone download mature content.