The differences grammar system between English and Bahasa Indonesia may result in translation changes. Therefore, grammatical equivalence in translating the two languages is very important to achieve closest meaning. The objective of study is to investigate the students’ ability in translating grammatical equivalence as well as to find out common errors made by students. The study is limited only on three grammatical categories namely person, tenses and voice. The data is collected by giving test for 20 respondents and the data was analyzed by using descriptive quantitative method. The participants of this study are 20 students. They are taken from the Sixth Semester English Department Students of State Institute for Islamic Studies (STAIN) Salatiga in the Academic Year of 2012/2013 which attended translation II. The result of the study showed that there are 2(10%) students got excellent level, 15(75%) students achieved good level and 3(15%) students gained fair level. However, in general, the result is good. Furthermore, in students’ translation work were founded errors that make their translation inaccurate and unacceptable. The use of inappropriate word, addition of information and omission are some errors displayed in students’ translation. Word-for-word translation applied by students also made their translation sound unnatural and uneasy to read.