We investigated cross-sectional associations of body composition and weight change with polychlorinated biphenyls (PCB) and organochlorine pesticides/pesticide metabolites measured in blood collected at the baseline of the Physical Activity for Total Health study of postmenopausal, overweight women living in the Seattle, Washington metropolitan area. Indicators of greater adiposity were associated with lower plasma concentrations of most PCBs with six or more chlorine atoms. This pattern was observed for current weight, body mass index, fat mass percent, subcutaneous abdominal fat, intra-abdominal fat, waist circumference, hip circumference, waist-to-hip ratio, and maximum adult weight. Conversely, PCB 105, PCB 118, and p,p'-DDE were generally increased or showed no association with these variables. Weight gain since age 35 was associated with lower concentrations of almost every organochlorine we studied, and past weight loss episodes of at least 20 pounds (≥9.1 kg) were associated with higher concentrations. Our results have implications for epidemiologic studies of organochlorines in terms of covariates that may be important to consider in statistical analyses, particularly as such considerations may differ importantly by specific analyte. Our finding of increased organochlorine concentrations with past weight loss episodes may have public health significance; however, this association requires confirmation in longitudinal studies.