This study investigated the replicability of a previously proposed personality typology of posttraumatic stress disorder (PTSD, and explored stability of cluster membership over a 6-month period. Participants with current PTSD (n = 156) were drawn from the Collaborative Longitudinal Personality Disorders Study (CLPS). The CLPS project tracked a large sample of individuals who met criteria for 1 of 4 target diagnoses (borderline, schizotypal, avoidant, and obsessive-compulsive) and a contrast group of individuals who met criteria for depression but no personality disorder. A cluster analysis using scales from the Schedule of Nonadaptive and Adaptive Personality yielded 3 clusters: “internalizing,” “externalizing,” and “low pathology.” Using K-means cluster analysis, the results did not replicate previous work. Using Ward's method, the hypothesized 3- cluster structure was confirmed at baseline but did not demonstrate temporal stability at 6 months.