ABSTRACTrnThis study is entitled ” A Study on the Errors in Constructing Passive SentencernMade of the Eleventh Grade Students of Minor Seminary St. Rafael OepoirnKupang in the School Year 2012/2013”. This study is conducted in order tornanswer the following questions: (1) Do the eleventh grade students of MinorrnSeminary of St. Rafael Oepoi Kupang commit errors in constructing passivernsentences? and (2) What are the most common errors made by the eleventh gradernstudents of Minor Seminary St. Rafael Oepoi Kupang in constructing passivernsentences? The objectives of this study are as follows: (1) To find out whether orrnnot the eleventh grade students of Minor Seminary St. Rafael Oepoi Kupangrncommit errors in constructing passive sentences. (2) To find out the most commonrnerrors committed by the eleventh grade students of Minor Seminary St. RafaelrnOepoi Kupang in constructing passive sentences. The method applied in this studyrnwas normative survey method, and the writer used test as instrument.rnThe result of study shows that the eleventh grade students of minor Seminary St.rnRafael Oepoi Kupang committed errors in constructing passive sentences. Thernmost common errors committed by the eleventh grade students of Minor SeminaryrnSt. Rafael Oepoi Kupang is misformation (9.81%). It followed by misorderingrn(8.19%), omission (3.78%) and addition (0.67%). Based on the result of datarnanalysis, the writer suggest: (1) The English teacher of the eleventh grade studentsrnof Minor Seminary St. Rafael Oepoi Kupang should give the students morernpractice in constructing passive sentence. (2) The students should consider of thernimportance of the grammar in general and English passive construction inrnparticular.