The article is a brief synopsis of the phenomenon of errors in writing. It sees error as a process in language development rather than as a final product. The article distinguishes the difference between an error and a mistake. It broadly categorizes the study of error into two categories: linguistic approaches and non-linguistic approaches. In this article the study is based on the linguistic approach which is of two types: the contrastive analysis approach and the error analysis approach. The author argues that most of the studies in error analysis attempt to classify a learner's error. Errors are generally divided into two categories: intra-lingual errors and interference errors. The article also discusses the studies of other scholars on this topic. It suggests that work on known rather than hypothesized errors are more fruitful. The error based approach proposed for the Nepalese context is of course a pedagogical one, and does not deny the validity of contrastive explanations for some errors. The results of this approach are significant to the teacher in that they help him assess the level of achievement of the learner and by implication the teaching content for the future. (Rajeev Ranjan Singh 2007-01-17)