Child obesity is a public health problem. The onset may be early, even since the infancy. Recently, obesity has been considered an “inflammatory disease”, but even the latest studies provide little data on the extent of the inflammatory process of adipose tissue in the child. Natural nutrition prevents obesity. Interleukin-6 and ultra-sensitive C-reactive protein are immunological markers associated with obesity. According to literature data, leptin directly influences the weight. The research aims the assessment of immune markers - leptin, interleukin-6 and C-reactive protein - in naturally-fed children, aged 1-23 months, including revealing the influence of immune markers on the weight of the subjects included in the study.