The objective of the study is to get the empirical evidence as the answer to the problem question. It is about whether the English formative test for the tenth grade students of the first semester of SMA Negeri 46 Jakarta in the 2009/2010 academic year is reliable or not. In estimating the reliability, the writer used parallel form technique. The first test was September 11, 2009 and the second test was on October 20, 2009. In collecting the data, the writer chose the tenth grade students as the population and took 40 students as a sample. The method of this research is quantitative and kind of this research is correlation. The writer implemented Pearson?s Product Moment (PPM) formula for analyzing data. The result is rt = 0.299 and ro = 0.79. Because ro > rt, it means that there is a significant correlation between the English formative test scores made by the teacher and parallel test scores made by the writer or it can be said the English formative test for the tenth grade students of the first semester of SMA Negeri 46 Jakarta in the academic year is reliable. The writer hopes that this study will give the beneficial information that can be used by the teachers, readers and test makers.