Background and Aim: Researchers tend to understand children’ response to disease, hospitalization and their health and disease experiences for various reasons. The importance of information has increased the demand for qualitative research on children in order to gain sufficient and deep knowledge and understanding of their insights in this age group about health and disease so that we can plan for better physical, mental care and finally improve their quality of life by acquiring of necessary knowledge and information. Although ethical considerations in qualitative research are similar in different groups, ethical considerations are critical in this group considering the complex process of qualitative research and children’s vulnerable nature. This study was designed to determine the ethical considerations in qualitative research with children’s participation. Materials and Methods: In this review, Persian and English articles published in Scopus, PubMed, SID, Irandoc, Magiran and Google Scholar databases were searched with no time limit using main keywords of "Ethical Considerations and Qualitative Research "or" Qualitative Research and Children ". The title and abstract of all articles were studied, duplicate and non-related articles were deleted, and contents of related articles were later analyzed. Ethical Considerations: This study has been approved by the Vice Chancellor for Research and Technology, and Ethics Committee of Shahid Beheshti University of Medical Sciences with the identification code: IR.SBMU.RESEARCH.REC1395.514. Publication of the results is carried out without bias, honestly and by citing the original reliable resources and references. Findings: Review of extract studies revealed general principles and ethical considerations in qualitative research with children’ participation are similar to other qualitative research and include attention to children’s participation, obtaining informed consent, ability to establish friendly and honest relationships, confidentiality and researcher’s sensitivity regarding publication of information and the imbalance of power. Conclusion: The findings suggest that the ability to establish a friendly relationship and win the child's trust play a very important role in the child's active participation in the research process as well as reducing the imbalance of power between the researcher and the child. So, it is essential to directly obtain information from the child. Obviously, the participation of children in research play a very important role in empowering and valuation to view of this vulnerable group. Thus, children' research must be carried out in a valuable, supportive and safe environment using appropriate methods to support their social and mental abilities, so that children easily express their opinions. Obtaining informed consent is an ongoing process that requires researcher’s patience and the guarantee that the child has understood the necessary information. In fact, obtaining children’ consent and encouraging them to make a decision strengthen the right to participate in or withdraw from the study, even if the parents are not willing to participate in the study. Therefore, the researcher must ask children in the process of research regarding their consent and participation in the study and must pay attention to their body language and gestures. The ethical principle of confidentiality of information is the challenging part because most children are not independent of their parents; therefore, interviewing with children alone is associated with some problems. Sometimes a child may also disclose information and researchers in support for vulnerable children, are forced to disclose certain informationin some cases. Two other very important concepts in the process of qualitative research with children’s participation include freedom, power, and thus an imbalance of power between researcher and participant. Establishing a friendly false relationship is immoral, so the way in which the researcher introduces him/herself, the language and clothes used and body language and manner of interacting with children have an impact on their relationship. The difference in children’s perception and experience of the world’s, compared with adults, and their different ways of communication, make it different and challenging to implement and observe ethical principles. Long tradition of the research on children mainly focused on getting information from families and caregivers instead direct research on children. Today, researchers should know that the concept of children research is defined as study ‘’with’’ child instead of "on" child. This fact highlights the importance of Children's participation and consent in the process of research. Even if researchers attend to active participation of children in the process, the concept of vulnerability is still dominant in them that require more caution for children's participation in the research. Children’s research must be conducted in a supportive and safe environment using appropriate methods, but different from adults, in order to support their social and mental abilities, so that, children easily express their opinions. The researcher must frequently review the thoughts and process through self-reflection and ask questions regarding whatever is doing in this process. Also, the researcher must clearly explain his/her motivation regarding the involvement of children. He must win trust and honesty of adults responsible for children and to do so, all forms of applied ethics should be completed in research and child-centered approach must be used in their study. Also, in qualitative research with children’s participation, in addition to the fact that methodology and ethical considerations should be assessed by knowledgeable individuals, the Research Ethics Review Committee should carefully examine the capacity and strength of children in a proposed research project. Please cite this article as: Moosavi S, Hasani P. Ethical considerations in qualitative research with children's participation. Med Ethics J 2017; 11(39): 63-73.