BACKGROUND: Memory abnormalities are among a central feature of posttraumatic stress disorder (PTSD). It is suggested that individuals with PTSD exhibit memory bias; while evidence shows poor memory function in these individuals. We aimed to examine memory bias in PTSD patients relative to controls and to explore an association between memory bias and memory function. METHODS: Forty-six women with DSM-IV PTSD, most of whom developed the disorder after interpersonal violence, and 68 non-trauma-exposed healthy control women were studied. Memory bias was assessed by a recognition memory task using negative, neutral, and positive words. Memory function was assessed by a standardized neuropsychological test battery. Depression and anxiety symptoms were assessed by self-report measures. RESULTS: Compared to controls, patients showed significantly greater negative bias scores (i.e., correctly recognized rates for negative words minus those for neutral words) and poorer memory function. Negative bias scores were significantly correlated with worse memory function in patients. When patients were divided into those with lower vs. normal memory function, the former patients had significantly greater negative bias than the latter patients and controls. Memory bias scores in patients were not significantly correlated with depression or anxiety symptoms, nor were they significantly different between patients with comorbid major depressive disorder and those without. LIMITATIONS: The cross-sectional design and absence of the trauma-exposed non-PTSD group limited our findings. CONCLUSIONS: PTSD patients have greater negative memory bias, which can be associated with poorer memory function. Our findings may provide an insight into the nature of memory abnormalities in PTSD.