This article presents a comparison of outpatient versus inpatient treatment for pelvic inflammatory disease (PID) according to patient characteristics, including age, race, parity, and clinical subgroups. Data for evaluation were obtained from the Pelvic Inflammatory Disease Evaluation and Clinical Health (PEACH) study of 831 women with mild-to-moderate symptoms of PID who participated in a randomized trial comparing outpatient and inpatient treatments. Pregnancy and infertility were the primary outcome measures. The inpatient treatment regimen consisted of intravenous cefoxitin (2 g every 6 hours) and intravenous or oral doxycycline (100 mg twice a day) for at least 72 hours followed by oral doxycycline (100 mg twice a day) for a total 14-day course. Women in the outpatient treatment group received a single intramuscular injection of cefoxitin (2 g) plus a single oral dose of probenecid (1 g) followed by oral doxycycline (100 mg twice daily) for 14 days. All patients were instructed to see that their partners also received appropriate treatment. Follow up included clinic visits at 5 and 30 days after treatment followed by telephone interviews every 3 months for the first year and every 4 months thereafter through June 2004. By this point, 541 patients were still in contact and had an average follow up of 84 months. At baseline, 75% of PEACH participants were black, 65% were under 25 years of age, and approximately 30% had a positive history of PID and current evidence of Neisseria gonorrhoeae and or Chlamydia trachomatis. Overall, the characteristics of each group were similar, but women in the outpatient treatment arm were more likely to have an intrauterine device in place and to have a diagnosis of bacterial vaginosis. The rate of pregnancy during the follow-up period was similar in both treatment groups regardless of race, history of PID, parity, baseline gonococcal and/or chlamydial genital infection, fever, white blood cell counts, or pelvic tenderness score. Women age 25 years or over who received outpatient treatment were more likely to become pregnant compared with younger women (odds ratio, 1.78; 95% confidence interval, 1.17–2.70), but the rates of infertility or live births were not different according to treatment group or any subgroup. Ectopic pregnancies were more frequent among women who received outpatient treatment, and all women with ectopic pregnancy were black. However, neither of these tendencies was statistically significant. There were no differences in the time to pregnancy either between treatment groups or according to subgroup. Self-reported PID recurrence and chronic pelvic pain were similar among all patients regardless of treatment or subgroup.