ABSTRACTrnThis study is entitled: ―An Analysis of Grammatical Error in thernFacebook Feeds of The Members of FBI Crew during the Period ofrnDecember 2012 to June 2013”. This study is conducted answer the followingrnquestions: (1) what are the types of Grammatical Errors in the Facebook feeds ofrnthe members of FBI Crew? (2) what are the most common errors occurred in thernfacebook feeds of the members of FBI Crew? The objectives of the study are (1)rnto find out the types of errors committed in facebook feed of FBI Crew, and (2) tornfind out the most common errors occurred in facebook feed of FBI crew. Thernmethod applied in this study was ―Descriptive Method‖ because it is used torndescribe the facts of the errors in the facebook feeds. The subject of the study wasrnthe facebook users in FBI Crew. There were 15 users in FBI Crew as the samplernof the study. The result of the analysis showed that the errors committed by thernuser in FBI Crew are Misformation 22 (51.16%), Misordering 6 (13.95%),rnAddition 6 (13.95%), and Omission 9 (20.93%). The total number of errors is 43.rnThe most frequent error is misformation. Based on the result of the study, thernwriter offers some suggestion to both the students of English Department and thernlecturer. For the students of English Department should learn more about Englishrngrammar in general and error taxonomies especially surface strategy taxonomy.rnThey should really pay attention on grammar when writing facebook feeds; it isrnbecause the most common errors committed by the user in FBI Crew arernmisformation. For the lecturer should pay more attention on the students grammarrnknowledge by providing practices on grammatical aspects particularly: wordrnorder, tenses, archi – forms and alternating forms. It should be started from thernbeginning semester.