Background: Treatment for partners of patients diagnosed with sexually transmitted infections (STIs), referred to as expedited partner therapy (EPT), is infrequently used in emergency departments (EDs). This was a pilot program to initiate and evaluate EPT through medication-in-hand ('take-home') kits or paper prescriptions. This study aimed to assess the frequency of EPT prescribing, the efficacy of a randomized best practice advisory (BPA) on the uptake of EPT, perceptions of ED clinicians regarding the EPT pilot, and factors associated with EPT prescribing. Methods: This pilot study was conducted at an academic ED in the midwestern US between August and October 2021. The primary outcome was EPT prescription uptake and the BPA impact was measured via chart abstraction and analyzed through summary statistics and Fishers exact test. The secondary outcome of barriers and facilitators to program implementation was analyzed through ED staff interviews (physicians, physician assistants, and nurses). A rapid qualitative assessment method for the analysis of the interviews was employed. Results: Fifty-two ED patients were treated for chlamydia/gonorrhea during the study period. EPT was offered to 25% (95% CI 15%-39%) of patients. EPT was prescribed twice as often (85% vs. 38%; p<0.01) when the interruptive pop-up alert BPA was shown. Barriers identified in the interviews included workflow constraints and knowledge of EPT availability. The BPA was viewed positively by the majority of participants. Conclusions: In this pilot EPT program, EPT was provided to 25% of ED patients who appeared eligible to receive it. The interruptive pop-up alert BPA significantly increased EPT prescribing. Barriers identified to EPT prescribing can be the subject of future interventions to improve ED EPT provision.