Though there may not be any official definition for either one of these fields, there are some generally accepted differences between media and public relations. The jobs are so similar that many firms may hire one individual to fill both roles, depending on the size of the company. These professionals help the company by not only dealing with the news media, but also projecting a consistent image of the company to the public in a way that is consistent with the desires of the company.
The main difference between media and public relations is that the term media relations is more limited. While public relations may include dealing with the media to some degree, media relations is a specialty. Therefore, those in strictly media relations positions will spend their time fielding calls from the media, identifying and "spinning" relevant news items, as well as writing press releases in an effort to keep the media informed about what is happening at the company. Depending on the desire of the company for free publicity, this could be a very busy position.
In fact, the demands of the media can be such a specialized field that some companies focus exclusively on this type of work. These media relations companies work with clients to get their names out and generate positive publicity. If a crisis or negative event does hit the company, these companies can also help by providing the media with a place to go where they know they can find the correct information. Thus, it helps the client by providing a centralized source that is not contradictory.
A public relations professional will do more than just deal with the media. In fact, a public relations person may not deal with media at all if the company decides to split its media and public relations segments into separate entities. In such as case, a public relations person may be responsible for outreach and serve as a liaison at special events, help plan those events, and even write a company newsletter so that employees can stay informed about what is happening.
No matter how the line is drawn between media and public relations, these jobs require a great deal of skill in mass communication. Professionals in these positions often must anticipate what information will be in demand, and know how to access it quickly. Further, they must do so in a way that does not make the company look bad. Most individuals in these fields hold at least a Bachelor's degree in communications or journalism. Some likely have experience working in the journalism field, either in print or broadcast media.