BACKGROUND/AIMS: There are no established guidelines for bowel preparation formulation for bowel cleansing, nor is there an optimal method of dealing with inadequate bowel cleansing. This study investigated bowel preparation formulation preferences and responses to bowel preparation situations using surveys. METHODS: The study surveyed 221 Korean lower gastrointestinal endoscopists from January to March 2015 and assessed their responses. RESULTS: The analysis indicated that 2-L polyethylene glycol (PEG) plus ascorbic acid (Asc) was the preferred method (76.5%) and most responders expressed satisfaction with the formulation in both potency and safety. To address poor bowel preparation on the day of colonoscopy, the majority of physicians chose to order ingestion of additional preparations and proceed with the colonoscopy as scheduled (56.6%). In addition, concerns about renal safety and electrolyte stability were raised regarding oral sodium phosphate. CONCLUSIONS: This study found that 2-L PEG+Asc was preferred for potency and safety, and that Korean endoscopists preferred to proceed with colonoscopy in poor bowel preparation situations rather than choose an alternate diagnostic modality.