Aim of this study was to investigate the incidence of Epstein-Barr virus (EBV) in patients diagnosed with undifferentiated nasopharyngeal carcinoma (UNPC) from the Northern Province of Jordan. All cases diagnosed with UNPC at King Abdullah University Hospital, Irbid, Jordan, between the years 1991 and 2009 inclusive were examined. Clinical data including age, gender, mode of presentation, site of biopsy were retrieved from pathology reports. In situ hybridization for (EBV)--EBERs was performed on cases with available paraffin blocks. Correlation between the different clinical variables and results of in situ hybridization was performed. There were 49 cases diagnosed with UNPC, only 39 specimens were available and studied. The median age of presentation was 41 years (range 9-70 years). Bimodal age distribution was noted, the first peak between 15 and 19 years of age and second between 60 and 64 years of age. Males were slightly more commonly affected than females. Cervical lymph node enlargement was the most common mode of presentation, followed by nasal obstruction. Biopsies were obtained primarily from the posterior nasal space, followed by cervical lymph node. Positive staining for EBERs by in situ hybridization was seen in 92.3% of the cases examined. There was no difference in detection rate between males and females or adults and pediatrics. All cases obtained from posterior nasal space were positive. The three negative cases were from biopsies obtained from cervical lymph nodes, which was statistically significant (P value <0.05). Nasopharyngeal carcinoma in Jordan is seen in both children and adults. It is associated with EBV infection in most, but not all cases. Posterior nasal space shows a more consistent staining for EBERs than cervical lymph nodes. The presence of other association with UNPC including cigarette smoking could possibly explain the cases with negative association.