Patients overweight or obese have more severe psoriasis than normal weight patients. Sometimes the excessive weight is related to a lack of efficacy of systemic treatment. We report a case of a psoriatic patient that experienced a dramatic improvement of psoriasis after weight loss surgery by gastric bandage. The great weight loss was accompanied by an effectiveness gain of response to infliximab. The mechanism responsible for this association is not certain, but it is probably multifactorial, involving genetic, environmental and immune-mediated factors. It has been suggested that adipose tissue can dramatically alter the volume of drug distribution and limit drug efficacy. Moreover, a reduction of weight could favour the response to therapy and remission of the disease, inducing an improvement in patient's quality of life. Gastric bandage has a scarce rate of complications, a fast recovery and scarce life-threatening complications. It should be considered in obese patient that not shown effectiveness to therapy.