Aim: Is to evaluate  the role of sentinel  lymph node biopsy (SLNB) in diagnosis of lateral nodal involvement in NO papillary thyroid cancer patients. Methods: 20 patients were included in this study; total thyroidectomy  with dissection of the central neck compartment was done in all patients. 0.5 ml of 2% methylene blue dye was injected into the primary tumour; blue stained SLN in lateral neck was identified and examined by frozen section. If any of the SLNs were positive on the frozen section, selective neck dissection (levels II-IV) was performed during same operation. In false-negative cases of SLNs reoperation was carried out after 1 week. Results: There were 6.7%false-negative rate; 100% specificity; 80% sensitivity, 93% negative predictive value;  100% positive predictive value, with 94.7% overall accuracy. Postoperative transient recurrent laryngeal nerve palsy occurred in 2 patients; but none of the patients had permanent  nerve palsy. One patient required calcium supplement on discharge; however, no patient developed permanent hypocalcaemia. Conclusion: SLNB is an easy and accurate method for assisting the diagnosis of metastasis in the lateral neck compartment, and it could reduce the risk of complications of thyroid surgery. We recommend  this technique  to support  the decision to perform selective neck dissection in NO papillary thyroid cancer patients.