A few studies have been conducted on the prevalence of partial posttraumatic stress disorder (PTSD), but points of agreement and disagreement between full and partial PTSD have not been fully investigated. We interviewed a representative sample of 6,258 subjects, ages 18-64 years, in household visits using the Korean version of the Composite International Diagnostic Interview (K-CIDI 2.1). "Partial PTSD" was defined as >/=1 symptom in each of the three symptom groups (Criteria B, C, and D) and duration of >/=1 month (Criterion E). Estimated lifetime prevalence of partial PTSD was 2.7%, and that of full PTSD was 1.7%. A "female gender" risk factor was significantly associated with both partial and full PTSD. The mean duration of partial PTSD was 6.5 years, which was not significantly different from the 5.7 year duration of full PTSD. Traumas associated with the development of partial rather than full PTSD were "natural disaster with fire" and "military combat" in men, and "witnessing a traumatic situation" and "learning about traumas to others" in women, whereas "threatened by others" was more associated with the development of full PTSD. The rates of multiple comorbid disorders and of comorbid major depressive disorder and dysfunctions in work during the 1-month period prior to interview did not differ significantly between the partial and full PTSD groups. In conclusion, partial PTSD did not differ significantly from full PTSD in terms of duration, comorbidity, and dysfunction, but they differed markedly in terms of associated trauma types.