To examine the feasibility, acceptability, and initial efficacy of a technology-based weight loss intervention for urban, low-income mothers.Eighteen obese, ethnic minority, socioeconomically disadvantaged mothers in the first year after childbirth were randomly assigned to either: 1) technology-based intervention, which included empirically supported behavior-change strategies, daily skills, and self-monitoring text messages with personalized feedback, biweekly counseling calls from a health coach, and access to a Facebook support group, or 2) usual-care control.After 14 weeks of treatment, the technology-based intervention participants had significantly greater weight loss (-2.9 ± 3.6 kg) than usual care (0.5 ± 2.3 kg; adjusted mean difference: -3.2 kg, 95% confidence interval -6.2 to -0.1 kg, P = .04). One-third of intervention participants (3 of 9) and no control participants lost > 5% of their initial body weight at follow up.Results suggest the potential for using technology to deliver a postpartum weight loss intervention among low-income racial/ethnic minorities.