BACKGROUND Several studies have shown a high incidence of metal allergy after minimally-invasive repair of pectus excavatum (MIRPE). We postulated that MIRPE is associated with a significant release of trace metal ions, possibly causing the allergic symptoms. METHODS We evaluated the concentration with chromium, cobalt and nickel in blood, urine and tissue in patients prior to MIRPE and in patients who underwent an explantation of the stainless-steel bar(s) after three years. RESULTS Our study group consisted of 20 patients (mean age 19 years) who had bar explantation and our control group included 20 patients (mean age 16 years) prior to MIRPE. At the time of bar removal we detected significantly elevated concentrations of chromium and nickel in the tissue compared to patients prior to the procedure (p<0,001). We also found a significant increase in the levels of chromium in urine and nickel in blood in patients three years post MIRPE (p<0,001). Four patients temporarily developed symptoms of metal allergy, all had elevated metal values in blood and urine at explantation. CONCLUSIONS Minimally-invasive repair of pectus excavatum can lead to a significant trace metal exposure.