Objective: Faculty-training on blueprinting is necessary to make medical teachers aware of threats to the attributes of assessment. The experiences and challenges of preparation and moderation of the online ML Web Session are discussed so as to facilitate the readers to conduct such activities. Methods: GSMC-FAIMER Regional Institute, Mumbai, India chose "Blueprinting in Assessment" for Web Discussion in January 2018, as a part of the GSMC-FAIMER Fellowship Programme. 32 participants were involved in an asynchronous manner, using Listserv Online Discussion Forum, from 1st to 31st January 2018. A sequential flow of the activities was aligned with chronological sequence of pre-defined objectives. Reflections were taken at the end of the month. Results: Comparison of Pre-test and Post-test analysis showed statistically significant improvement in percentage scores (p<0.05). The participants appreciated the ML Web Discussion Session activities in their reflections. Conclusion: This ML Web Session achieved the learning objectives, increased the knowledge and led to a deeper understanding of blueprinting in assessment, through comprehensive, though asynchronous, peer-group discussion.