Little research exists on the need for, barriers to, and acceptability and effectiveness of psychosocial support services among Latinas with breast cancer, despite their increased risks of psychosocial distress. This formative research study identifies barriers to and benefits and components of an effective peer support counselor intervention for Spanish-speaking Latinas recently diagnosed with breast cancer. Analysis was based on interviews of 89 Latino cancer patients referred to psychosocial services; 29 Spanish-speaking survivors of breast cancer; and 17 culturally competent advocates for Latinos with cancer. Results indicate that interventions should begin close to diagnosis; build self-care skills; be culturally competent and emotionally supportive; provide language appropriate cancer information; encourage self-expression; and address lack of access to and knowledge of services. Creating such psychosocial programs with input from survivors and advocates who have similar self-identities to patients would improve quality of life in diverse and underserved populations.