This chapter provides a comprehensive guide to maintaining *Caenorhabditis elegans* in the laboratory. It covers various aspects, including acquiring strains from the Caenorhabditis Genetics Center (CGC), preparing growth media, culturing worms on petri plates, growing worms in liquid medium, cleaning contaminated stocks, obtaining synchronous cultures, and freezing and recovering worms for long-term storage. The CGC, established in 1979 and moved to the University of Minnesota in 1992, provides C. elegans strains and information to researchers. It aims to have at least one mutant allele of each published gene and all chromosome rearrangements available. Researchers can request strains for free, while commercial organizations are charged a fee. Requests should include details about the desired strains and the intended use. C. elegans is typically grown on Nematode Growth Medium (NGM) agar, which is prepared by mixing NaCl, agar, peptone, and water. The medium can be seeded with *E. coli* OP50, a uracil auxotroph, to provide a food source. NGM plates are prepared using a peristaltic pump and can be stored for several weeks. Worms can be transferred using methods such as "chunking," where a chunk of agar is moved to a new plate, or using sterilized filter paper to absorb moisture and pick up worms. Transferring frequency depends on the genotype, temperature, and intended use of the worms. Heterozygous and mating stocks should be transferred every 1-3 generations, while homozygous stocks can be allowed to starve for several weeks between transfers. Large quantities of C. elegans can be grown in liquid medium using S Medium and concentrated *E. coli* OP50. Overcrowding can lead to dauer formation, so it is best to grow just one generation of worms before harvesting. Contaminated stocks can be cleaned using methods such as chunking, serial transfer, or treating with a hypochlorite solution. Mold can be removed by chunking and serial transfer, while bacterial and yeast contaminants can be killed with a hypochlorite solution. Synchronous cultures can be obtained by axenizing eggs and incubating them in M9 Buffer overnight. Dauer animals can be induced by adding dauer-inducing pheromone or by allowing the culture to grow without bacteria for several days. C. elegans can be frozen and stored indefinitely in liquid nitrogen using glycerol and a gradual cooling process. Freshly starved young larvae (L1-L2 stage) survive freezing best. The CGC uses two freezing solutions: Liquid Freezing Solution and Soft Agar Freezing Solution. Worms can be recovered from frozen stocks with a recovery rate of 35-45%. The author acknowledges contributions from Robert Herman, Ann Rougvie, and Todd Starich.This chapter provides a comprehensive guide to maintaining *Caenorhabditis elegans* in the laboratory. It covers various aspects, including acquiring strains from the Caenorhabditis Genetics Center (CGC), preparing growth media, culturing worms on petri plates, growing worms in liquid medium, cleaning contaminated stocks, obtaining synchronous cultures, and freezing and recovering worms for long-term storage. The CGC, established in 1979 and moved to the University of Minnesota in 1992, provides C. elegans strains and information to researchers. It aims to have at least one mutant allele of each published gene and all chromosome rearrangements available. Researchers can request strains for free, while commercial organizations are charged a fee. Requests should include details about the desired strains and the intended use. C. elegans is typically grown on Nematode Growth Medium (NGM) agar, which is prepared by mixing NaCl, agar, peptone, and water. The medium can be seeded with *E. coli* OP50, a uracil auxotroph, to provide a food source. NGM plates are prepared using a peristaltic pump and can be stored for several weeks. Worms can be transferred using methods such as "chunking," where a chunk of agar is moved to a new plate, or using sterilized filter paper to absorb moisture and pick up worms. Transferring frequency depends on the genotype, temperature, and intended use of the worms. Heterozygous and mating stocks should be transferred every 1-3 generations, while homozygous stocks can be allowed to starve for several weeks between transfers. Large quantities of C. elegans can be grown in liquid medium using S Medium and concentrated *E. coli* OP50. Overcrowding can lead to dauer formation, so it is best to grow just one generation of worms before harvesting. Contaminated stocks can be cleaned using methods such as chunking, serial transfer, or treating with a hypochlorite solution. Mold can be removed by chunking and serial transfer, while bacterial and yeast contaminants can be killed with a hypochlorite solution. Synchronous cultures can be obtained by axenizing eggs and incubating them in M9 Buffer overnight. Dauer animals can be induced by adding dauer-inducing pheromone or by allowing the culture to grow without bacteria for several days. C. elegans can be frozen and stored indefinitely in liquid nitrogen using glycerol and a gradual cooling process. Freshly starved young larvae (L1-L2 stage) survive freezing best. The CGC uses two freezing solutions: Liquid Freezing Solution and Soft Agar Freezing Solution. Worms can be recovered from frozen stocks with a recovery rate of 35-45%. The author acknowledges contributions from Robert Herman, Ann Rougvie, and Todd Starich.