Aim: Evaluation of the transcript expression profile of selected genes encoding leptin and orexin A and B receptors with the oligonucleotide microarray technique (Affymetrix, HG-U133A). Material and method: Peripheral blood mononuclear cells (PBMC) of 4 patients suffering from AN and fulfilling all criteria according to ICD-10 and DSM IV [14, 15] were analyzed. Two of these patients suffered from the restrictive form of AN (AN-R) and the remaining two suffered from the binge eating/purging form (AN-BP). The control group consisted of 4 patients not suffering from any eating disorders. The studied material consisted of RNA isolated from patients' PBMC. Obtained RNA was used to study the expression profile of selected genes at the transcript level with the oligonucleotide microarray technique (Affymetrix, HG-U133A). Hierarchical clustering (Cluster v 3.0) for six and then eight oligonucleotide microarrays was used to analyze the results. Results and conclusions: Hierarchical clustering singled out two clusters for AN-R, AN-BP and control group patients. Based on the results of hierarchical clustering performed for six and then eight oligonucleotide microarrays showing different expression profiles for genes coding selected orexigenic (OXA and OXB) and anorexigenic (LEP) proteins, we may assume that this technique differentiates the two forms of AN: restrictive (AN-R) and binge eating/purging (AN-BP).