Aim.  This paper reports a study to assess stress, well-being and supportive resources experienced by mothers and fathers of children with rare disabilities, and how these variables were affected by an intensive family competence intervention. Background.  Despite diagnosis-specific studies, little overall knowledge exists about life-consequences for families of children with rare disorders. Method.  We used a prospective design with baseline data and two follow-ups (at 6 and 12 months) after an intervention. The intervention aimed at empowering parents in managing their child's disability. Parents from all parts of Sweden visiting a national centre for families of children with rare disabilities were consecutively selected (n = 136 mothers, 108 fathers). Instruments of parental stress, social support, self-rated health, optimism and life satisfaction and perceived physical or psychological strain were used. Stratified analyses were carried out for mothers and fathers, and related to parental demands: single mothers, full-time employment, participation in a parent association, child's age and type of disability. Results.  We found high parental stress, physical and emotional strain among mothers, especially among single mothers. Fathers showed high stress related to incompetence, which decreased after the intervention. Decreased strain was found among full-time working mothers and fathers after the intervention. Parents’ perceived knowledge and active coping and mothers’ perceived social support were increased at follow-up. Factors related to parents’ overall life satisfaction (57–70% explained variance) changed after the intervention, from being more related to internal demands (perceived strain, incompetence and social isolation) to other conditions, such as problems related to spouse, paid work and social network. Conclusion.  Parents, especially fathers and full-time working parents, may benefit from an intensive family competence programme.