The scope of this article is to describe the Portuguese Weight Control Registry (PWCR) methodology and the participants currently enrolled specifically with respect to their individual and family weight history, previous weight loss attempts, and psychosocial characteristics. One hundred and ninety-eight adults (age: 39.7±11.1 years; BMI: 26.0±3.9 kg/m2), 59% women, filled out a questionnaire about demographics, health-related behaviors and motivation, and methods and strategies used to lose and/or maintain weight loss. Participants reported an average weight loss of 17.4 kg for an average of 29 months. Concerning the number of weight loss attempts, 73% of participants reported a maximum of three attempts of going on a diet, and 34% indicated only one attempt to lose weight in the past. The PWCR now features a considerable number of successful long-term weight loss maintainers in Portugal. Participants will be followed over the next years to learn about their characteristics and weight loss strategies in further detail, as well as to identify predictors of continued weight loss maintenance.