Amongst the various complications reported for single visit endodontics, incidence of post endodontic pain (PEP) is the most common. To evaluate and compare the incidence, duration, intensity and nature of post endodontic pain (PEP) in single visit endodontic treatment, following biomechanical preparation (BMP), using K files with Step Back Technique, Protaper Next with Crown down Technique and Passive Ultrasonic Instrumentation (PUI) along with Protaper Next. 75 patients, with asymptomatic irreversible pulpitis in Maxillary anterior teeth were selected and treated with single sitting root canal treatment, by a single operator. Patients were randomly divided into 3 groups, Control (K files using step back technique), Experimental 1 (Protaper Next using crown down technique) and Experimental 2 (Protaper Next along with PUI). Patients were recalled, examined and asked to fill up questionnaire after 3hrs, 24 hrs, 48 hrs and 7 days of wearing-off of anaesthesia. On the basis of response given in the feedback forms, PEP was evaluated for incidence, duration, intensity and nature. Statistical analysis of the data was carried out using Chi square test and level of significance (p < 0.05) was evaluated. Incidence of PEP was identical in the two experimental groups, which was lower than the control group. Statistically, difference in the incidence of pain, amongst the three groups was found to be non-significant. The duration of pain was longest in Control group, with more patients, experiencing pain, whereas it was least in Experimental group 2. Across the groups, maximum patients experienced mild, continuous pain. Majority of patients experience PEP that is mild, continuous, localised and precipitated by trigger factors. It lasts longer, with hand instruments.