Background and Aim: Agrammatism is a phenomenon of neuropsychological relevance which has been recently investigated from conceptual and empirical aspects. The present study focuses on grammatical deficit in agrammatic aphasia. We evaluated the impairment of correct use of tenses of Persian verbs in agrammatic Broca's aphasia.Methods: Eight patients (mean age 57 years) participated in this descriptive - analytic study. They were classified as agrammatic Broca's aphasia according to the Persian aphasia test, their CT Scan and MRI reports and other inclusion criteria. All patients but one were monolingual native speakers of Persian (Farsi). The other individual was bilingual whose dominant language was Persian. All subjects had a left unilateral brain lesion for at least one year after the onset of brain damage. The written sentence completion and picture sentence completion tests were designed and performed.Results: Results do not indicate significant difference between Past Tenses of verb; however, comparison of means showed best scores in Simple Past, Past Continuous, Present Perfect and Past Perfect, respectively. A main result of this study was significant difference between the mean of responses to Past Tense in comparison with Present Tense and Future (p=0.02).Conclusion: Use of tense is impaired in agrammatic Broca's aphasia in Persian. Our findings point out that use of Past Tense is impaired significantly more than the other tenses of verb.