Focus groups have been widely used in health research to explore the perspectives and experiences of individuals regarding health, illness and the health system, and to understand its sociocultural and contextual factors. Migrant health is increasingly a research topic of interest nationwide. Immigrants are recognized as a group that tends to underuse healthcare services, which has a negative impact on their health and their integration into the host society. Research on migrants’ access to and utilization of healthcare services has been based mainly on quantitative data. However, qualitative research through focus groups may contribute to gain a deeper understanding of the challenges that migrant populations face in seeking healthcare. In this chapter we reflect on the potential, advantages and challenges of the focus group technique in health services research, based on a study which was conducted to understand better the perceptions and experiences related to access and utilization of healthcare services of immigrants in Portugal; the study examines the data from the perspectives of the immigrants as well as health workers. Six focus groups were conducted with 20 immigrant community leaders and 32 health workers. We first contextualize the study and then focus on the use of the focus group technique, because of its potential for providing rich and valuable information within a diverse cultural setting. Furthermore, focus groups contribute with dynamic ideas and discussion, which do not arise from individual interviews. Then we describe the process of cattying out the focus groups. The focus group dynamic stimulated lively discussions around access and utilization of healthcare services among immigrant populations. Participants shared their experiences and views, and expressed their disagreements with factors influencing migrants’ access and utilization of health services. Finally, we debate the strengths as well as the challenges of using this technique. The focus group dynamics helped eliminate defensive attitudes regarding, for example, immigrants’ legal status. However, the sensitive nature of this topic and the potential effect of group interaction may have inhibited the disclosure of experiences and perceptions of some participants, especially among the health workers, regarding the denial of care to undocumented immigrants. Overall, during the focus group sessions, participants were not merely “study subjects” but could actively participate in the process of reflecting on proposals for overcoming the identified barriers and improving access and utilization of health services among immigrants. The use of focus group technique was valuable in that it produced better knowledge on the real health needs of immigrants and health workers in their daily lives, increased awareness on the topic and helped identify opportunities for effective action.