The Epidermal growth factor receptor (EGFR) family plays an important role in carcinogenesis. CIMAher® (Nimotuzumab), is a humanized monoclonal antibody, which recognizes EGFR with high affinity. The aim of this work was to perform the direct labeling of Nimotuzumab with [99mTc(CO)3(H2O)3]+ as precursor and to evaluate its labeling conditions, in vitro and in vivo stability and biodistrution in normal C57 BL/6J mice. 99mTc(CO3)-Nimotuzumab labeling yields were up to 90%. More than 90% of the complex remained intact after 24 h of incubation with L-Histidine (1/300 molar ratio). Biodistribution studies in normal mice were also performed. Inmunoreactivity was confirmed by cell binding assays with A431cells. These results encourage the evaluation of the potential role of 99mTc(CO)3-Nimotuzumab as a novel tumor-avid radiotracer for targeting in vivo EGFR expression.