This article, based on the other part of the research entitled EFL Learners’ Concord Mastery and their grammatical Deviations carried out by the writer, aims at describing to what degree EFL learners have committed grammatical deviations from 3 types of concord: subject-verb concord (SVC), subject-complement concord (SCC), and subject-object concord (SOC) and to what extent those deviations became mistakes and errors. With the population of 120 EFL learners of three classes of the third year students of the English Department of the Faculty of Languages, Literature, and Arts of the State University of Padang, and with one class of them chosen as the sample comprising of 32 subjects by cluster-sampling technique, the data were gathered throu...