Microbial composition profiling techniques powered by Next-Generation sequencing are becoming routine in microbiomics and metagenomics studies. However, these analytical techniques can suffer from significant bias from collection to analysis. The ZymoBIOMICS Microbial Community Standard is designed to assess bias and errors in the extraction methods of a microbiomics workflow. The Microbial Community Standard mimics a mixed microbial community of well-defined composition, containing three easy-to-lyse Gram-negative bacteria, five tough-to-lyse Gram-positive bacteria, and two tough-to-lyse yeasts. Acting as a defined input from the beginning, the Microbial Community Standard can guide construction and optimization of entire workflows and can also be used as a routine quality control. Theoretical Composition Based on Genomic DNA: Listeria monocytogenes – 12%, Pseudomonas aeruginosa – 12%, Bacillus subtilis – 12%, Escherichia coli – 12%, Salmonella enterica – 12%, Lactobacillus fermentum – 12%, Enterococcus faecalis – 12%, Staphylococcus aureus – 12%, Saccharomyces cerevisiae – 2%, and Cryptococcus neoformans – 2%.