Background & Aim: Midwife as a provider of services such as premarriage consultation. Pre-and- post delivery cares, caring for neonatal and treatment of some obstetric diseases, should be familiar with the legal aspects of her duties. Correct knowledge about the rule and regulation tends to the reduction of offence and its consequences.Meanwhile study of the midwifes knowledge provides opportunity for proper educational planning which can be an important index of in evaluating the treatment condition of the cases under study. The aim of this study was to determine the level of knowledge about the legal aspects of the duty in midwives employed in Mazandararn province.Materials & Methods: In this descriptive study 140 midwives employed at private and governmental hospitals were collected in question divided in two sections comprising individual information (5 questions) And knowledge assaying (55 questions with three choices) and the scores foregiven as 0- 55 the validity and accuracy of the questionnaire were confirmed using a index of kronkenbakh (78%) in a pilot study. The obtained data were analyzed using descriptive analysis and SPSS software.Results: From total of 140 midwives 10.7% had post diploma study certificate, 86.4% had BSc and 2.9% had MSc. Their experiences varied from 1 to 30 years (mean 11.1 years). The mean knowledge of the cases under study was 41.2 and the lowest and highest obtained scores were 14 and 51 respectively. It was found that 64.2% of them had good knowledge (41-55 scores), 35% medium knowledge was poor in some aspects and percentage of correct answer to some of the question was less than 50.Conclusion: knowing that knowledge of 40% cases under study was poor to medium identification of the causes is very important. Therefore these questions with less correct answer should be considered more, and in order to make the information more applicable and increase sensitivity of midwives towards rules certain management be implemented.