PURPOSE: The purpose of this study was to assess the prevalence and radiographic characteristics of the nuchal ligament ossification on lateral cephalometric radiographs in Koreans. SUBJECTS AND METHOD: I review and interpreted the lateral cephalometric radiographs from 4,558 patients (1,857 males and 2,701 females, age range from 2 to 79 years) who visited the Kyungpook National University Dental Hospital from January 1, 2008 to February 3, 2009. I grouped the shapes of nuchal ligament ossification as round, rod-like, and segmented shape. And localized the ossification as the involvement of anterior cervical vertebral body. The data were analyzed by using chi-squared test with two-tailed and at a 5% significance level. RESULTS: Among those who showed the nuchal ligament ossification, the mean age of the 143 males was 51.1 and that of the 97 females was 48.0 years. It was not observed completely below teens, and was observed 1% in twenties, 6.1% in thirties, 18.6% in forties, and 26.3% over fifties. It was significantly prevalent in older age group (P<0.01) and in males than females among the same age group (P<0.05). The shapes of nuchal ligament ossification were as follows in order of frequency : rod-like (49.2%), round (30.4%), and segmented (20.4%). The highest involvement of ossification was found at the level of C5 (67.9%), C4 (29.2%), C6 (22.9%), C3 (3.3%), C7 (2.9%), C2 (0.8%), and C1 (0.4%). CONCLUSION: The nuchal ligament ossifications on lateral cephalometric radiographs were showed as round, rodlike, or segmented shape. The nuchal ligament ossification is often observed after the age of 40 and is observed more frequently in males than females. The highest shape of nuchal ligament ossification was rod-like shape and the highest involvement of cervical spine was C5.