At the end of education, midwifery students have to acquire the minimum capabilities of their professional job services. The aim of this study was to determine achieving rate to learning minimums in obstetric Units and its performance obstacles by midwifery students. In this descriptive study, all of senior midwifery students studying last term in 1389- 90were selected through census method. Data collection tools were a questionnaire related to minimums of learning in traineeship– internship courses of obstetric and pregnancy Unit. After the data were analyzed by SPSS software as frequency distribution and total evaluating through multigrades scale as desired, relatively desired and undesired. According to data, rate of achieving to learning minimums was estimated 61.11% undesired and 33.33% desired; In addition, only 30 percent of students were able to do the number of birth according to minimum learning. The most important obstacles of learning performance in obstetric unit included tasks completion with intern and resident, selection of inappropriate clinical environment, scarce number of patients, low skilled and inexperience teacher tolarge number of students, respectively. In some reported cases, students could not attain learning minimums or their experience was weak at achieving skills, subsequently, that insufficient education relatively would effect on the quality of education as well as the health of mothers. Therefore, it is necessary to revise the educational minimums; and then according to nature of every clinical skills and suggested cases, they should be defined, adjusted and coincided with students' needs. Moreover, due largely to limited number of patients and educational environment of hospitals, it is suggested that manikin, moulage, CDs, none educational hospitals are used for promotion of clinical teacher skills in students education and reeducation courses.