© 2018 Elsevier Inc. Recruiting children with chronic disease or subgroups of children (low income, obese, specific ages, types of cancer) from clinics and schools for research studies may be particularly difficult. While some have deemed such groups as hard to reach, these groups may be more accurately described as either hard to contact or hard to engage. This is not because children are unknown to the school or clinic but because the researcher's ability to communicate directly with targeted children prior to enrollment is limited. The purpose of this paper is to describe barriers and possible strategies for recruiting hard to contact or hard to engage subgroups of children. Barriers identified in recruiting these children were: naïve to research, communication style and technology, parent/guardian burden, parental conditions and concerns, child stressors and distractions, and research setting. Possible strategies include: pre-consent education, information sheets about study, identifying preferred method of communication, meaningful and appropriate incentives, coordinating recruitment visit with regularly scheduled clinic appointments or school schedule, demonstrating research equipment, informing staff about research study, negotiating creatively for space for research, and emphasizing confidentiality of data. Consideration of barriers to recruitment and utilization of strategies to counteract these barriers is critical to the success of a study involving subgroups of children.