OBJECTIVES: This study examined differences between nurses and paraprofessionals in implementation of a home visiting program for low-income, first-time parents during pregnancy and the first 2 years of the child's life. METHODS: Mothers were randomly assigned to either a nurse-visited (n = 236) or a paraprofessional-visited (n = 244) condition. Nurse- and paraprofessional-visited families were compared on number and length of visits, topics covered, number of program dropouts, and relationship with home visitor. RESULTS: On average, nurses completed more visits than paraprofessionals (28 vs 23; P < .001) and spent a greater proportion of time on physical health issues during pregnancy (38% vs 27%; P < .001) and on parenting issues during infancy (46% vs 32%; P < .001). Paraprofessionals conducted visits that lasted longer and spent a greater proportion of time on environmental health and safety issues (15% vs 7% pregnancy; 15% vs 8% infancy; P < .001). While home visitors were viewed equally positively by mothers, nurses had fewer dropouts than did paraprofessionals (38% vs 48%; P = .04). More paraprofessional-visited families than nurse-visited families experienced staff turnover. CONCLUSIONS: Nurses and paraprofessionals, even when using the same model, provide home visiting services in different ways.