This study aimed at determining the mathematics achievement and English language proficiency and the degree of the relationship between variables among the fourth year students of Saint Mary's Academy of Capiz during the school year 1998-1999. This descriptive correlational research used the simple random sampling method for the selection of the 68 students representing the 75.56% of the total population. A validated researcher-made mathematics achievement test was used in this study to find out the level of mathematics achievement of the students. The reliability of the items in the researcher made-test was determined using the SPSS software. The Language Proficiency Test was used to determine the level of the English Language Proficiency. The statistical tools used were the Pearson's r to test the degree of relationship between the two variables, mathematics achievement, and English Language proficiency; the One Way ANOVA, and the t-test in determining the significant differences among groups of participants in terms of their mathematics achievement and English language proficiency. For the descriptive analysis; the statistical tools used were the means and standard deviations in determining the levels of mathematics achievement and English language proficiency. The study revealed that the students, taken as a whole, had an average level in their mathematics achievement and English language proficiency. When they were classified according to gender, both groups, were average in their performance in mathematics and English. When they were classified according to mental ability, the above average, average and below average obtained an average performance in both English and mathematics. Significant differences were noted in the mathematics achievement of the students when they were classified as to mental ability. A significant relationship was observed between the mathematics achievement and the language proficiency of the fourth year students.