Background and Aims. rs822393 (-4522C/T) genetic variant is associated with hypoadiponectinemia and other metabolic parameters. The aim of our investigation was to analyze the effects of a hypocaloric diet with Mediterranean dietary pattern during 9 months according to genetic variant rs822393 of ADIPOQ gene. Methods and Results. A sample of 269 obese patients was enrolled. Anthropometric and serum parameters (lipid profile, insulin, homeostasis model assessment (HOMA-IR), glucose, C reactive protein, and adipokines) were determined, at basal time and after 3 and 9 months. All patients were genotyped in the rs822393. The genotype distribution was as follow; 176 patients (65.4%) CC, 83 patients CT (30.9%), and 10 patients TT (3.7%). After dietary intervention, the following parameters improved in non-T allele carriers; BMI, weight, fat mass, waist circumference, systolic blood pressure, insulin levels, HOMA-IR, leptin, total cholesterol, and LDL-cholesterol improved significantly. HDL-cholesterol (delta:
5.7
±
1.1
mg
/
dl
vs.
1.0
±
0.8
mg
/
dl
;
p
=
0.01
), serum adiponectin (delta:
14.4
±
2.0
ng
/
dl
vs.
7.1
±
3.1
ng
/
dl
;
p
=
0.02
), and adiponectin/leptin ratio (delta:
0.54
±
0.1
vs.
0.22
±
0.09
ng
/
dl
;
p
=
0.03
). Basal and postintervention HDL cholesterol, adiponectin levels, and adiponectin/leptin levels were lower in T-allele carriers than non-T Allele carriers. Conclusion. T allele carriers showed lower levels of HDL-cholesterol, adiponectin, and adiponectin/leptin ratio than non-T allele carriers. A medium-term hypocaloric diet with a Mediterranean partner increased adiponectin levels, ratio adiponectin/leptin, and HDL-cholesterol in non-T allele carriers.