What makes a difference in the academic performance in English Language Arts and Mathematics for Puerto Rican English language learners with and without disabilities? A mixed-methods research design was used to examine the factors that influence the academic achievement in English of Puerto Rican English language learners with and without disabilities, in a bilingual school. The 2005-2006 seventh grade cohort from the Duarte school, a high-poverty, low achieving school in the Northeast was examined with the goal of understanding what factors most influenced achievement. Quantitative and qualitative archival data from achievement tests, attendance records, and cumulative records were examined. The study revealed several significant factors that correlated to performance results in English language arts and mathematics. Most significant were the levels of performance in the native language and the impact of attendance on performance. The qualitative record review corroborated these findings and revealed that program consistency was a critical factor in the performance of these students. The results of the study will add to the empirical research on successful practices for the education of students identified as limited English Proficient, both with and without disabilities.