The aims of this research were to find out: 1) the students‟ level of
competence in using simple past tense, 2) the types of errors made by the students of
using simple past tense. This research was descriptive. The data was taken on 3rd
January 2014 in the first semester students of English Department of Muhammadiyah
University of Purwokerto in academic year 2013/2014. Thirty four respondents were
chosen as the sample. The technique used to collect the data was test in the form of
sentence translation from Indonesian to English. After analyzing the data, it was
revealed that the mean of students‟ competence in using simple past tense was
57.45%. It indicated that the students‟ competence in using simple past tense
belonged to fair category. It was also revealed that the errors made by students in
using simple past tense were in four error types, namely overgeneralization,
ignorance of rule restrictions, incomplete application of rules, and false concept
hypothesis. It was proved by the result of each error; overgeneralization were 6.62%,
ignorance of rule restrictions were 12.5%, incomplete application of rules were
8.61%, and false concept hypothesis were 33.97%.