The purpose of this study is to determine the differences of grammar learning, if any, between the EFL classes in which native language (L1) is sometimes used and only target language (L2) is used. Participants were 42 prep year students from one of the universities in Turkey. They have been studying English for 9 months, and now they are in level D that is equal to B1 or B2 in CEFR. Study was committed to students in level D which is still in progress. In the experimental group, which is first class, no mother language, Turkish was used. In the other class that is comparison group, some usage of mother language (L1) was seen in the class. In terms of comparing the two EFL classes, results show that two classes are nearly same in learning grammar. The percentage of the first class was 69% that is the average and normal score for a level D class. Percentage of 66.50 may seem less, but the difference was only 2.50 point between the classes. Teaching grammar in one of the EFL classes require so many responsibilities both for the teacher and the students, nevertheless choosing which way to use in the class is still an unanswered question for teachers. In this study, the results show that the success of the students is not directly related to the teaching style. (Contains 1 table.)