This paper investigates and analysis the common interference of mother tongue, were committed by the students who are native of Tamil language, in writing English as a second language. The purpose of this current study is to reveal the common interference of the first language Tamil with its rules and structures in writing ESL. This study was conducted by using the qualitative research method and an essay was taken, from the participants, as a tool of this study . Data were collected from 50 Advanced level students who study at the government schools and these written samples were gathered from the Tamil native students who passed English language in their O/Level examination. The collected data were analyzed and identified the interference of mother tongue,in writing English as a second language, are in punctuation, capitalization, spelling, vocabulary, wrong use of pronoun, word order or sentence structure, preposition, conjunction and adjective. Besides this study will help to our students to develop their writing skills of L2, also to correct them. As well, this article will assist the teachers of ESL to approach the students in learning English as a second language.