This thesis comprises of two equally important topics. The thesis deals with eating disorders and a mindfulness technique presented as an approach towards treating the mentioned problem. Goal of the research was to test the effectiveness of mindfulness techniques in treating eating disorders and to test the implementation quality of a newly created program. The program based on mindfulness interventions was conducted in “BEA Center”, while the evaluation of technique effectiveness was conducted in three program cycles, each lasting 10 weeks. Mixed approach method was used in the research. Questionnaires were used to test the effectiveness before the program and 10 weeks after it. Focus group method was used to test the program’s implementation quality and the participants’ perception of the influence of the program on themselves. Twenty-three female participants of the program were examined in the research and they had the following eating disorders: binge eating disorder,bulimia nervosa and anorexia nervosa.The results of quantitative data processing show statistically significant differences in 8 out of 10 examined constructs. This partially accepts the first hypothesis dealing with the effectiveness of a mindfulness-based treatment program. Results have shown that the program has positively influenced self-esteem levels, reduced dissatisfaction of physical appearance, increased expression and identification of emotions, enhanced regulation and management of emotions and observation, description, nonjudgement and non-reactivity to inner experience skills. The second hypothesis of the research involved examining the effects of applied mindfulness techniques to the symptoms of eating disorders. It is confirmed because the participants have shown a desirable influence of mindfulness observation, reflection and acceptance skills on their feelings and thoughts without the need for the experience to change towards their own personal problems tied to eating disorders. Last research question was directed towards examining the implementation quality of the program. It was found that the participants’ perception on the comprehensiveness, variety of mindfulness methods and techniques and close relationships with other participants positively influences the participants’ motivation to treat their problems. On the other hand, the participants expressed a need for designing a structured support for practicing mindfulness techniques and a longer duration of the program.