Medical ethics principles are universally accepted. However, each country can make some modifications and develop specific clarifications reliable with countries' existing culture. As with any profession, dentists have a responsibility to their patients and communities in which they practice, more over it is essential that dental professionals understand and practice honestly the code of ethics which is approved by the ministry of health in Iraq. Researcher aim is to highlighting the importance of ethics in general and dentistry as specific; understand the different echelons in knowledge between professional's dentists and to identify dental intern level of understanding the ethics responsibilities were given in the questionnaire. A cross-sectional questionnaire study was accomplished among three groups of dentist in Nineveh. The sample size of 240 participants was calculated from the total number of dentists (979) in Nineveh allocated between intern resident, general practitioners and dental specialist. For data collection we use a revised specialized questionnaires published by Satish Deo and his colleagues in 2018. A self-administered, 40 -itemed questioner encompassing four sections: general information, knowledge, attitude, and practice of ethics in dental healthcare were employed. Data are statistically analyzed shows that most dentists' age is ranged between two levels (less than 28 y and from 36 to 43y) with mean age (36.66 years). In spite of that females are forming the high percentage (63.8) in practitioners group but no sex predilection in the total result. Specialist show high significant scores in the statistical analysis when compared with practitioners and interns. The last group shows the least level in knowledge. Concluding from this study that reputation to be part of medical healthcare persons make dentist forced to follow the ethical roles in the country where he live and should be an ideal example for others in the society as we are the mirrors of each other's.