Excessive weight gain among inmates is frequently observed by correctional health care providers; however, there is little published research on weight change during incarceration. This study describes the weight and weight changes among women incarcerated in a unified correctional system (prison and jail). The women were interviewed and had their height and weight measured. At baseline, 33.0% were of normal weight, 34.9% were overweight, and 32.1% were obese. Participants were reweighed after a median of 14 days; the women had gained an average of 1.1 lbs/week (SD: 2.1 lbs, range: -3.3 to +9.2 lbs) with 71% of women gaining weight. Women incarcerated for 2 weeks or less at time of study enrollment experienced higher average weight weekly gains than those incarcerated longer than 2 weeks (1.7 lbs vs. 0.8 lbs).