We intend to study twenty patients of one orthopaedic surgeon (SCM) undergoing total hip replacement in the supine position. Patients must be English speaking and of light skin color to standardize the contrast of the site marking. The study will be discussed with the patient in the clinic setting before the surgical date. Patients will be randomized into either using a chlorhexidine based skin preparation solution (Chloraprep® (chlorhexidine gluconate 2% w/v and isopropyl alcohol 70% v/v; Enturia Inc., Leawood, KS, USA)), or an iodine based skin preparation solution (Duraprep® (Iodophor 0.7% and isopropyl alcohol 74% w/w; 3M Healthcare, St. Paul, MN, USA)). Patients with allergies to either chlorhexidine or iodine will not be included in the study. These solutions are both the current gold standard of clinical care and are routinely used in the Johns Hopkins Bayview Medical Center. No differences have been shown in infection rates for total hip arthroplasty between these solutions.