Although research with hard‐to‐reach populations is necessary to deepen the social work knowledge base and improve services to these groups, recruiting members of hard‐to‐reach populations for research projects is often a challenging process. Frequently, non‐probability sampling is used to obtain participants. However, the difficulties and limitations associated with this process in quantitative research are rarely discussed in depth in the literature. Sampling issues can significantly impact a research project, delaying it, extending it or even causing the premature termination of a project. Challenges to recruitment can limit the type of research that is completed, impact the knowledge base or introduce threats to validity through sampling bias. Using a preliminary quantitative study on parental engagement with child protective services as an illustration for the discussion, the challenges of non‐probability sampling with a hard‐to‐reach population and the implications for research practice are explored and discussed. Implications for future research practice are considered.