Natural products have been isolated from fungi, archaea and eubacteria, microorganisms with several strategies to cope with such a harsh environment. Among these habitats, marine microorganisms are being extensively studied for their ability to produce antimicrobial compounds. Currently, antimicrobial resistance is a significant health issue. Considering the rapid emergence of antimicrobial resistance, we need to look for new sources of antimicrobial compounds. This chapter summarises the psychrophiles, antibiotic resistance mechanism and cold adaptation. Among cold-temperature extremophiles, the particular focus has been on the marine environment due to its richness in bioactive compounds. One of the less explored environments is the cold soil habitat. However, minimal data displays various classes of natural products, like lantibiotics, spirotetronates, microcins, synoxazolidinones and indole alkaloids. Furthermore, we explained that different microorganisms producing an unclassified natural product with a promising source for future bioprospecting are discussed. © 2024 Taylor & Francis Group, LLC.