Introduction Pelvic inflammatory disease (PID) is a spectrum of illness ranging from mild illness to more severe forms including tubo-ovarian abscess, hydrosalpinx, pyosalpinx, oophoritis (THPO). The objective of the study was to report rates and clinical characteristics of females presenting to the ED with a diagnosis of THPO in relationship to the presence or absence of sexually transmitted infections (STIs). Methods A database of ED patient encounters occurring from April 18, 2014, to March 7, 2017 was created. Analysis of women diagnosed with THPO and who had testing for gonorrhea, chlamydia, or trichomonas by nucleic acid amplification testing or who had a vaginal wet preparation was performed. Patient demographics, ED diagnoses, laboratory tests, medications administered in the ED, and medications prescribed were examined. Categorical variables were summarized as count and percentages and analyzed using the Chi-square test. Continuous variables were summarized as the mean and standard deviation and analyzed using the t-test. All statistical tests were two-sided with a significance level of 0.05. Results THPO was diagnosed in 0.3% (56/17,905) of patient encounters. There were 50% (28/56) of women with THPO admitted to the hospital. There were 25.0% (12/48) women who received a positive test result for Neisseria gonorrhoeae, Chlamydia trachomatis, and/or Trichomonas vaginalis. Women with THPO were significantly older, more likely to be infected with gonorrhea, and more likely to be diagnosed with sepsis and PID (P<.05 for all). Conclusions THPO is an infrequently encountered entity in the ED. A diagnosis of STI, PID, and sepsis can accompany these presentations. Although an uncommon diagnosis, ED providers must be attentive to patients presenting with pelvic symptoms that could be consistent with THPO to mitigate any complications that may arise and to direct the appropriate treatment.