The following protocol is intended for the simultaneous extraction of DNA and RNA (total nucleic acids, or TNA) from various soil and sediment samples. The protocol was designed based on two protocols published by Henckel et al. (1999) and Griffiths et al. (2000), with several critical modifications. Recently, we have added option to include an ammonium aluminium sulfate salt for soils with high humic content (Braid et al., 2003). The result is a highly flexible and streamlined protocol, which delivers high yields of nucleic acids with quality suitable for all downstream molecular applications from most types of soil and sediment samples. Please cite Angel et al. (2012).