This study is to know whether or not there is a contribution of vocabulary mastery to the students? reading comprehension. It was a non experimental study referring to the approach of correlation analysis in the form of Pearson Product Moment. The scope of the study was on contribution of vocabulary mastery to the students? reading comprehension of SMK Muhammadiyah 4 West Jakarta. The research of study was conducted in semester 1 on July 2010. The result of the study revealed that ro is higher than rt; 0.393 > 0.361 in the level of significance ? = 0.05 or 5%. It means that null hypothesis is rejected and alternative hypothesis is accepted. Thus, there was a positive contribution of vocabulary mastery to the students? reading comprehension of SMK Muhammadiyah 4 West Jakarta.