This article discusses the offense of citizen journalists in presenting content through online media. The current form of communication in the online media changed from one-way communication to two-way communication. Recipients also change roles from news receptors only to simultaneously become a messenger. The change in communication patterns has resulted in citizen journalists who are responsible for presenting news around them. These journalists however generally preformed their jobs to a particular group of people through ออนไลน์ media such as blogs web sites and social media sites. Without the training in journalism. For the dissemination of content through online media citizen journalists have a great variety of contents and present them in the formats of messages pictures videos live broadcasts via many important social media such as Facebook Twitter etc. and the created websites. The content is published in either legal or illegal manner. The nature of the offense of the citizen journalists appearing in the online media can be identified as follows: 1) presenting false news in the online world 2) presenting political violence content 3) presenting erotic content 4) sexual and obscene 5) serious language expression 6) cyber bullying and cybercrimes: youth falling victim to cyber bullying; being threatened to the verge of scary annoyance and anger; being sexually harassed or abusive with obscenity 7) providing defamatory content and 8) providing offensive materials. In addition this article aims to present the ethics related to the offense of citizen journalists. The laws relating to the offense of four citizen journalists are the Constitution of the Kingdom of Thailand BE 2560 The Criminal Code Act BE 2496 the Act that shall apply the provisions of Part 1 of the Civil and Commercial Code 1992 and the Act on Offenses Against Computer (No. 2) BE 2560; and City Reduces Offender Law.