Obesity is a chronic condition that is prevalent in black women. The Obesity Reduction Black Intervention Trial (ORBIT) was a randomized controlled weight loss and weight-loss maintenance (WLM) trial. Participants (N = 213) were randomized to the intervention or control groups in August 2005 and September 2006. Follow-up data were collected 6 and 18 months after randomization. The main outcome was change in weight and BMI from baseline to 18 months. The mean weight at baseline was 104.9 kg, and the mean weight loss in the intervention group at 6 months was 3.0 kg and a gain of 0.2 kg in the control group (mean difference between groups in weight change at 6 months, adjusting for baseline weight and cohort, -3.27 kg; 95% confidence interval (CI), -4.50 to -2.05 kg; P < 0.001). Both groups gained weight between 6 and 18 months (mean 1.0 kg in the intervention group and 0.1 kg in the control group). However, intervention participants lost significantly more weight than control participants during the 18-month intervention (adjusted mean difference between groups at 18 months, -2.83 kg; 95% CI, -4.71 to -0.95; P = 0.003). At 18 months, intervention participants were more likely than control participants to have lost at least 5% of baseline weight (24% vs. 12%, P < 0.04). Our results indicate that the ORBIT program did promote weight loss and weight-loss maintenance. However, the results also clearly illustrate there is more to learn about what will contribute to meaningful weight loss and maintenance in this population.