The Academy of Breastfeeding Medicine defines “breastfeeding” as “the mother/child act of milk transference”. It is right of every child and every mother. Breastfeeding is the only natural nutrition for newborns and infants, it provides the child with all the energy and nutrients needed for the first months of life, half or more nutritional needs within the next six months and up to one third of nutritional needs during the second year of life. Mother’s milk has the ability to adapt to child’s energy and nutritional needs. Breastfeeding brings many benefits for both- mother and child, in the moment and for the long term. In order for doctors and nurses to carry out evidence-based practice, they have to follow new researches that can be nowadays found summarized into a systematic reviews. Although systematic reviews can provide many good things, they may vary in quality. The aim of this study was to evaluate the methodological quality of systematic reviews on the subject of breastfeeding, using one of the tools for assessing the methodological quality of the systematic reviews- AMSTAR. AMSTAR was first created in 2007, and the name stands for “A Measurement Tool to Assess Systematic Reviews”. We use AMSTAR to develop and evaluate the reviews, as a guide to conduct systematic reviews, and as an aid in teaching about systematic literature reviews. For this Master’s thesis several electronic databases were searched: Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, Ovid MEDLINE from 1946 and CINAHL. Among the obtained works, fifty were selected and evaluated with AMSTAR tool in two ways of grading- dichotomous and granulated. We have analyzed whether the publication of the AMSTAR tool is related to changes in the methodological quality of published systematic reviews, whether there is a correlation between the number of authors with the estimated quality of systematic reviews and whether there are differences in quality between Cochrane systematic reviews and systematic reviews published outside Cochrane Collaboration. Finally, the difference between grades obtained by the dichotomous and granulated method of assessing the quality of systematic reviews using the AMSTAR tool were analyzed. We have also collected and presented the epidemiological characteristics of the systematic reviews included in this paper. Research has shown that studies published before AMSTAR (M = 6.00, sd = 2.00; M = 6.43, sd = 2.14) were better rated on average than those published later (M = 4.96 , sd = 2.35; M = 6.08, sd = 2.08), regardless of whether the grades were obtained with dichotomous or granulated AMSTAR. The number of authors was poorly correlated with the number of points on the dichotomous (r = 0.14) and the granular AMSTAR (r = 0.21). It was found that in both modes of assessment there is a statistically significant difference between points of systematic reviews included in Cochrane Collaboration (t = 2.39, df = 48, p <0.01, t = 1.83, df = 48, p <0.01) - Cochrane Collaboration studies on average have higher points. The average number of points obtained with dichotomous AMSTAR (M = 5.02, sd = 2.33) was lower than the average score obtained with granulated AMSTAR (M = 6.10, sd = 2.06).