The poor prognosis of patients with high-grade glioma has led to the search for new therapeutic strategies. More than half of these tumors overexpress Epidermal Growth factor Receptor (EGFR). h-R3 is a humanized monoclonal antibody that recognize the EGFR external domain with high affinity, inhibiting tyrosine kinase activation. In order to evaluate safety, immunogenicity and preliminary efficacy of h-R3 in newly diagnosed high-grade glioma patients, we conducted a Phase I/II trial. Patients received six weekly infusions of h-R3 at the dose of 200 mg in combination with external beam radiotherapy. Twenty-nine patients (mean age, 45 years and median KPS 80) were entered into the study. Tumor types were: glioblastoma (GB) (16 patients), anaplastic astrocytoma (AA) (12 patients) and anaplastic oligodendroglioma (AO) (1 patient). All patients underwent debulking surgery or biopsy before entering the trial. The antibody was very well tolerated. No evidences of grade 3/4 adverse events were detected. None of the patients developed acneiform rash or allergic reactions. One patient developed a positive anti-idiotypic response. Objective response-rate was 37.9% (17.2% complete response, 20.7% partial response) while stable disease occurred in 41.4% of the patients. With a median follow up time of 29 months, the median survival is 22.17 months for all subjects. Median survival time (MST) is 17.47 months for GB, whereas MST is not reached for AA patients.