To investigate the contribution of small non-coding RNAs, including microRNAs, to stress response in C. elegans, we examined their expression changes using Illumina deep-sequencing technology. Stress conditions we examined include heat shock, Pseudomonas aeruginosa (PA-14) and L1 arrest. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Total RNAs were purified from wild-type young adult animals that were exposed to each stress condition, and used for cDNA library preparation for small RNAs. As for the L1 arrest sample, first wild-type embryos were collected and cultured without a food source in M9 buffer for 48 hrs with rotation, and then RNAs purified from L1 animals in a developmentally arrested state were used for the library preparation. These cDNA libraries established were sequenced with Illumina Genome Analyzer II.