BACKGROUND: Lifestyle interventions regularly rely on study staff to implement the intervention and collect outcomes data directly from study participants. This study describes the experiences of project staff in two randomized controlled trials of a postpartum lifestyle intervention to reduce risk factors for type 2 diabetes in Latinas. Latinas are the fastest growing minority group in the U.S. and have the highest rates of type 2 diabetes after a diagnosis of gestational diabetes mellitus. The challenges of implementing lifestyle interventions for postpartum women have been poorly documented. METHODS: A qualitative focus group was conducted with eight staff members (five health educators and three health interviewers) involved in Proyecto Mama and Estudio Parto. The discussion was audio recorded, transcribed, and coded in NVivo. Focus group topics included: 1) participant recruitment, 2) participant retention, 3) implementation of the lifestyle intervention, 4) assessment of behavior change, 5) overall challenges and rewarding aspects of the trial, and 6) recommended changes for future trials. RESULTS: Key themes emerged regarding enabling factors and barriers to implementing a lifestyle intervention in postpartum Latinas. Enabling factors included: a) the staff's belief in the importance of the intervention, b) opportunities associated with the longitudinal nature of the trial, c) belief that the staff could empower participants to make behavior change, d) benefits of flexible intervention sessions, and e) connection with participants due to shared cultural backgrounds. Barriers included: a) participant stressors: home, food, and financial insecurity, b) low health literacy, c) issues related to recent immigration to the continental U.S., d) handling participant resistance to behavior change, e) involvement of family members in assessment visits, f) limitations of the assessment tools, and g) time limitations. CONCLUSIONS: Findings highlight the challenging contexts that many study participants face, and shed light on the potentially influential role of health educators and interviewers in intervention implementation and data collection. Specific recommendations are made for strategies to improve adherence to diabetes prevention programs in postpartum underserved and minority populations in this challenging, transitional period of life. TRIAL REGISTRATION: NCT01679210 . Registered 5 September 2012; NCT01868230 . Registered 4 June 2013.