Background: Making impressions to replicate oral conditions and tooth morphology is an integral part of prosthetic dentistry. Polyvinyl siloxane impression materials have the best fine detail reproduction and elastic recovery of all available materials. They are provided in wide range of viscosities, rigidities, and working and setting times. Impression techniques can be categorized as monophase or dualphase. Aim of the study: To assess efficacy of custom tray and stock tray made up of polyvinylsiloxane to evaluate linear dimensional accuracy. Materials and methods: The present study was conducted in the Department of prosthodontics of institute of dental studies and technologies (IDST). For the study, a metallic mandibular dentulous die was fabricated to represent the mandibular dentulous arch. Prominent reference points for cast measurements on either side were marked. Stainless steel mandibular dentulous stock trays were selected for the putty wash 2-step impression techniques, to provide sufficient space for both putty and wash impression material. Perforated acrylic resin custom trays of thickness 3 mm with 2 mm space in between the occlusal surface of teeth and inner tray walls were fabricated. The impressions techniques of polyvinyl siloxanes, utilized in this study, were as follows. Group A: Putty wash 2-step technique with polyethylene spacer using stock tray, Group B: Single mix technique utilizing medium viscosity in a custom tray, Group C: Multiple mix technique utilizing heavy viscosity and low viscosity combination in custom trays. For each impression technique, 5 impressions were made and a total of 15 impressions were obtained. Results: We observed that the least change in dimension for antero posterior was observed to be in group C. For lateral dimension, the least change was seen in group A. For vertical dimension, Group A was seen to have least change in dimensions. The results on comparison were found to be statistically significant. Conclusion: Within the limitations of the present study, it can be concluded that two step impression technique with stock tray provide significant accuracy in impressions as compared to custom trays. Keywords: Stock tray, polyvinylsiloxane impression, dimensional stability