Introduction and background: Pain and its control is one of the health problems in the world. Vein Puncture is one of the most usual invasive procedures performed by nurses. So finding methods to decrease the pain caused by vein puncture is very important. Objectives: The present study was planned to evaluate the efficacy of applying Diclofenac gel and EMLA (Eutectic mixture of local anesthetics) ointment on vein puncture pain severity with vein catheter in the patients undergoing cesarean section. Design, Setting and conduct: This is a randomized, single blind, placebo controlled clinical trial that was conducted on 90 women undergoing cesarean section in Imam Ali Hospital’s maternity section in Amol city. Between 9th of April 2010 and 10th of June 2010 eligible patients were randomly divided into EMLA group (E group), Diclofenac group (D group) or Placebo group (P group) in equal numbers. Study Entry Requirements: aged 18 to 40 years; don’t have any defect in terms of mental and visual and verbal ability; Patients who doesn’t have any sensitivity to local anaesthetics or allergy to NSAIDs; haven’t used analgesics during the previous 24 hours; don’t have Favism, methemoglobin, liver and kidney disease, asthma, skin allergies, skin dermatitis, wound in the area assigned for intervention, active gastrointestinal bleeding, allergies to topical anaesthetics and non steroidal anti-inflammatory drugs included in this study. Study Exclusion: if the insertion vein catheter be unsuccessful in the first attempt or the caesarean section become an emergency operation. Interventions: for the Patients in D Group used diclofenac gel, E Group used EMLA ointment and P Group used Vaseline ointment in the area of the catheter insertion one hour before catheter insertion. Main outcome measures: The severity was pain. Background variables: age, history of the installation of vein catheter, having therapeutic support systems, level of monthly income and the level of the patient’s education.