Objective: The aim of this study was to investigate the efficacy of diffusion-weighted magnetic resonance imaging (DW-MRI) as a reliable imaging modality for detecting metastatic neck lymph nodes of head and neck squamous cell carcinoma (SCC). Methods: Thirty-two patients underwent positron emission tomography computed tomography (PET/CT) and DW-MRI were evaluated. Histopathologic analysis of lymph node metastases was used as the gold standard for assessment. We analyzed differences in sensitivity, specificity, accuracy, positive predictive value and negative predictive value among the imaging modalities using the Chi-square test. Their discriminative power evaluated using the Receiver-Operating Characteristic curve and calculation of the area under the curve. The correlation between ADCmin and SUVmax was calculated using the Spearman test. SPSS 24 was used for statistical analyses. P value of 0.05 indicates a statistically significant difference. Results: A total of 32 patients with 50 neck dissections with head and SCC included. Sensitivity, specificity, accuracy, positive and negative predictive value of neck palpation was 72%, 60%, 70%, 62% and 80% respectively. Sensitivity, specificity, accuracy, positive and negative predictive value of DW-MRI was 87.5%, 96.2%, 92%, 95.5% and 89.3% respectively, according to ADCmin cutoff value 0.82×10-3s/mm2 . Sensitivity, specificity, accuracy, positive and negative predictive value of FDG-PET/CT was 91.7%, 100%, 96%, 100% and 92.9%, respectively, according to SUVmax cutoff value 3.4. For all neck dissections, there was a statistically significant inverse correlation between ADCmin and SUVmax (P<001). Conclusion: DW-MRI may be as reliable as FDG-PET/CT in detecting cervical lymph node metastases. DWI and FDG PET/CT can play a complementary role in clinical evaluation. Further research is needed.